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11g Release 1 (11.1)

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11 Schema Objects and Oracle JVM Utilities

This chapter describes the schema objects that you use in Oracle Database Java environment and Oracle JVM utilities. You run these utilities from a UNIX shell or from the Microsoft Windows DOS prompt.

Note:

All names supplied to these tools are case-sensitive. As a result, the schema, user name, and password should not be changed to uppercase.

This chapter contains the following sections:

Overview of Schema Objects

Unlike conventional Java virtual machine (JVM), which compiles and loads Java files, Oracle JVM compiles and loads schema objects. The following kinds of Java schema objects are loaded:

To ensure that a class file can be run by Oracle JVM, you must use the loadjava tool to create a Java class schema object from the class file or the source file and load it into a schema. To make a resource file accessible to Oracle JVM, you must use the loadjava tool to create and load a Java resource schema object from the resource file.

The dropjava tool deletes schema objects that correspond to Java files. You should always use the dropjava tool to delete a Java schema object that was created with the loadjava tool. Dropping schema objects using SQL data definition language (DDL) commands will not update auxiliary data maintained by the loadjava tool and the dropjava tool.

What and When to Load

You must load resource files using the loadjava tool. If you create .class files outside the database with a conventional compiler, then you must load them with the loadjava tool. The alternative to loading class files is to load source files and let Oracle Database compile and manage the resulting class schema objects. In Oracle Database 10g, the most productive approach is to compile and debug most of your code outside the database, and then load the .class files. For a particular Java class, you can load either its .class file or the corresponding .java file, but not both.

The loadjava tool accepts Java Archive (JAR) files that contain either source and resource files or class and resource files. When you pass a JAR or ZIP file to the loadjava tool, it opens the archive and loads its members individually. There are no JAR or ZIP schema objects.

Note:

When you load the contents of a JAR into the database, you have the option of creating a database object representing the JAR itself. For more information, refer to "Database Resident JARs".

A file, whose content has not changed since the last time it was loaded, is not reloaded. As a result, there is little performance penalty for loading JAR files. Loading JAR files is a simple, fool-proof way to use the loadjava tool.

It is illegal for two schema objects in the same schema to define the same class. For example, assume that a.java defines class x and you want to move the definition of x to b.java. If a.java has already been loaded, then the loadjava tool will reject an attempt to load b.java. Instead, do either of the following:

Resolution of Schema Objects

All Java classes contain references to other classes. A conventional JVM searches for classes in the directories, ZIP files, and JAR files named in the CLASSPATH. In contrast, Oracle JVM searches schemas for class schema objects. Each class in the database has a resolver specification, which is Oracle Database counterpart to CLASSPATH. For example, the resolver specification of a class, alpha, lists the schemas to search for classes that alpha uses. Notice that resolver specifications are per-class, whereas in a classic JVM, CLASSPATH is global to all classes.

In addition to a resolver specification, each class schema object has a list of interclass reference bindings. Each reference list item contains a reference to another class and one of the following:

Oracle Database facility known as resolver maintains reference lists. For each interclass reference in a class, the resolver searches the schemas specified by the resolver specification of the class for a valid class schema object that satisfies the reference. If all references are resolved, then the resolver marks the class valid. A class that has never been resolved, or has been resolved unsuccessfully, is marked invalid. A class that depends on a schema object that becomes invalid is also marked invalid at the time the first class is marked invalid. In other words, invalidation cascades upward from a class to the classes that use it and the classes that use these classes, and so on. When resolving a class that depends on an invalid class, the resolver first tries to resolve the referenced class, because it may be marked invalid only because it has never been resolved. The resolver does not resolve classes that are marked valid.

A developer can direct the loadjava tool to resolve classes or can defer resolution until run time. The resolver runs automatically when a class tries to load a class that is marked invalid. It is best to resolve before run time to learn of missing classes early. Unsuccessful resolution at run time produces a ClassNotFound exception. Furthermore, run-time resolution can fail for the following reasons:

The loadjava tool has two resolution modes:

If you can, defer resolution until all classes have been loaded. This avoids a situation in which the resolver marks a class invalid because a class it uses has not yet been loaded.

Schema Object Digest Table

The schema object digest table is an optimization that is usually invisible to developers. The digest table enables the loadjava tool to skip files that have not changed since they were last loaded. This feature improves the performance of makefiles and scripts that call the loadjava tool for collections of files, some of which must be reloaded. A reloaded archive file might also contain some files that have changed since they were last loaded and some that have not.

The loadjava tool detects unchanged files by maintaining a digest table in each schema. The digest table relates a file name to a digest, which is a shorthand representation or a hash, of the content of the file. Comparing digests computed for the same file at different times is a fast way to detect a change in the content of the file. This is much faster than comparing every byte in the file. For each file it processes, the loadjava tool computes a digest of the content of the file and then looks up the file name in the digest table. If the digest table contains an entry for the file name that has an identical digest, then the loadjava tool does not load the file, because a corresponding schema object exists and is up to date. If you call the loadjava tool with the -verbose option, then it will show you the results of its digest table lookups.

Normally, the digest table is invisible to developers, because the loadjava tool and the dropjava tool keep the table synchronized with schema object additions, changes, and deletions. For this reason, always use the dropjava tool to delete a schema object that was created with the loadjava tool, even if you know how to drop a schema object using DDL..

Compilation of Schema Objects

Loading a source file creates or updates a Java source schema object and invalidates the class schema objects previously derived from the source. If the class schema objects do not exist, then the loadjava tool creates them. The loadjava tool invalidates the old class schema objects because they were not compiled from the newly loaded source. Compilation of a newly loaded source, for example, class A, is automatically triggered by any of the following conditions:

To force compilation when you load a source file, use the loadjava -resolve option.

The compiler writes error messages to the predefined USER_ERRORS view. The loadjava tool retrieves and displays the messages produced by its compiler invocations.

The compiler recognizes some options. There are two ways to specify options to the compiler. If you run the loadjava tool with the -resolve option, then you can specify compiler options on the command line. You can additionally specify persistent compiler options in a per-schema database table, JAVA$OPTIONS. You can use the JAVA$OPTIONS table for default compiler options, which you can override selectively using a loadjava tool option.

Note:

A command-line option overrides and clears the matching entry in the JAVA$OPTIONS table.

A JAVA$OPTIONS row contains the names of source schema objects to which an option setting applies. You can use multiple rows to set the options differently for different source schema objects. The compiler looks up options in JAVA$OPTIONS when it has been called by the class loader or when called from the command line without specifying any options. When compiling a source schema object for which there is neither a JAVA$OPTIONS entry nor a command-line value for an option, the compiler assumes a default value, as follows:

The ojvmtc Tool

The ojvmtc tool enables you to resolve all external references, prior to running the loadjava tool. The ojvmtc tool allows the specification of a classpath that specifies the JARs, classes, or directories to be used to resolve class references. When an external reference cannot be resolved, this tool either produces a list of unresolved references or generated stub classes to allow resolution of the references, depending on the options specified. Generated stub classes throw a java.lang.ClassNotfoundException, if it is referenced at runtime.

The syntax is:

ojvmtc [-help ] [-bootclasspath] [-server connect_string] [-jar jar_name] [-list] -classpath jar1:path2:jar2  jars,...,classes

For example:

ojvmtc -bootclasspath $JAVA_HOME/jre/lib/rt.jar -classpath classdir/lib1.jar:classdir/lib2.jar -jar set.jar app.jar

The preceding example uses rt.jar, classdir/lib1.jar, and classdir/lib2.jar to resolve references in app.jar. All the classes examined are added to set.jar, except for those found in rt.jar.

Another example is:

ojvmtc -server thin@scott:localhost:5521:orcl -classpath jar1:jar2 -list app2.jar
Password:password

The preceding example uses classes found in the server specified by the connection string as well as jar1 and jar2 to resolve app2.jar. Any missing references are displayed to stdout.

Table 11-1 summarizes the arguments of this command.

Table 11-1 ojvmtc Argument Summary

Argument Description

-classpath

Uses the specified JARs and classes for the closure set.

-bootclasspath

Uses the specified classes for closure, but does not include them in the closure set.

-server connect_string

Connects to the server using visible classes in the same manner as -bootclasspath.

connect_string thin|OCI

Connects to the server using thin or Oracle Call Interface (OCI) specific driver.

If you use thin driver, the syntax is as follows:

thin:user/passwd@host:port:sid

If you use OCI driver, the syntax is as follows:

oci:user/passwd@host:port:sid
oci:user/passwd@tnsname
oci:user/passwd@(connect descriptor)

-jar jar_name

Writes each class of the closure set to a JAR and generates stubs for missing classes

-list

Lists the missing classes.


The loadjava Tool

The loadjava tool creates schema objects from files and loads them into a schema. Schema objects can be created from Java source, class, and data files. The loadjava tool can also create schema objects from SQLJ files.

You must have the following SQL database privileges to load classes:

You can run the loadjava tool either from the command line or by using the loadjava method contained in the DBMS_JAVA class. To run the tool from within your Java application, do the following:

call dbms_java.loadjava('... options...');

The options are the same as those that can be specified on the command line with the loadjava tool. Separate each option with a space. Do not separate the options with a comma. The only exception for this is the -resolver option, which contains spaces. For -resolver, specify all other options in the first input parameter and the -resolver options in the second parameter, as follows:

call dbms_java.loadjava('..options...', 'resolver_options');

Do not specify the -thin, -oci, -user, and -password options, because they relate to the database connection for the loadjava command-line tool. The output is directed to stderr. Set serveroutput on, and call dbms_java.set_output, as appropriate.

Note:

The loadjava tool is located in the bin directory under $ORACLE_HOME.

Just before the loadjava tool exits, it checks whether the processing was successful. All failures are summarized preceded by the following header:

The following operations failed

Some conditions, such as losing the connection to the database, cause the loadjava tool to terminate prematurely. These errors are displayed with the following syntax:

exiting: error_reason

This section covers the following:

Syntax

The syntax of the loadjava tool command is as follows:

loadjava {-user | -u} user/[password][@database] [options]
file.java | file.class | file.jar | file.zip |
file.sqlj | resourcefile | URL...
  [-casesensitivepub]
  [-cleargrants]
  [-debug]
  [-d | -definer]
  [-dirprefix prefix]
  [-e | -encoding encoding_scheme]
  [-fileout file]
  [-f | -force]
  [-genmissing]
  [-genmissingjar jar_file]
  [-g | -grant user [, user]...]
  [-help]
  [-jarasresource]
  [-noaction]
  [-norecursivejars]
  [-nosynonym]
  [-nousage]
  [-noverify]
  [-o | -oci | oci8]
  [-optiontable table_name]
  [-publish package]
  [-pubmain number]
  [-recursivejars]
  [-r | -resolve]
  [-R | -resolver "resolver_spec"]
  [-resolveonly]
  [-S | -schema schema]
  [-stdout]
  [-stoponerror]
  [-s | -synonym]
  [-tableschema schema]
  [-t | -thin]
  [-unresolvedok]
  [-v | -verbose]
  [-jarsasdbobjects]
  [-prependjarnames]
  [-nativecompile]

Argument Summary

Table 11-2 summarizes the loadjava tool command arguments. If you run the loadjava tool multiple times specifying the same files and different options, then the options specified in the most recent invocation hold. However, there are two exceptions to this, as follows:

  • If the loadjava tool does not load a file because it matches a digest table entry, then most options on the command line have no effect on the schema object. The exceptions are -grant and -resolve, which always take effect. You must use the -force option to direct the loadjava tool to skip the digest table lookup.

  • The -grant option is cumulative. Every user specified in every invocation of the loadjava tool for a given class in a given schema has the EXECUTE privilege.

Table 11-2 loadjava Argument Summary

Argument Description

filenames

You can specify any number and combination of .java, .class, .sqlj, .ser, .jar, .zip, and resource file name arguments.

-proxy host:port

If you do not have physical access to the server host or the loadjava client for loading classes, resources, and Java source, then you can use an HTTP URL with the loadjava tool to specify the JAR, class file, or resource and load the class from a remote server. host is the host name or address and port is the port the proxy server is using. The URL implementation must be such that the loadjava tool can determine the type of file to load, that is, JAR, class, resource, or Java source. For example:

loadjava –u scott –r –v –proxy proxy_server:1020 http://my.server.com/this/is /the/path/my.jar
Password: password

When the URL support is used inside the server, you should have proper Java permissions to access to the remote source. The URL support also includes ftp: and file: URLs.

-casesensitivepub

Publishing will create case-sensitive names. Unless the names are already all uppercase, it will usually require quoting the names in PL/SQL.

-cleargrants

The -grant option causes the loadjava tool to grant EXECUTE privileges to classes, sources, and resources. However, it does not cause it to revoke any privileges. If -cleargrants is specified, then the loadjava tool will revoke any existing grants of execute privilege before it grants execute privilege to the users and roles specified by the -grant operand. For example, if the intent is to have execute privilege granted to only SCOTT, then the proper options are:

-grant SCOTT -cleargrants

-debug

Turns on SQL logging.

-definer

By default, class schema objects run with the privileges of their invoker. This option confers definer privileges upon classes instead. This option is conceptually similar to the UNIX setuid facility.

-dirprefix prefix

For any files or JAR entries that start with prefix, this prefix will be deleted from the name before the name of the schema object is determined. For classes and sources, the name of the schema object is determined by their contents. Therefore, this option will only have an effect for resources.

-encoding

Identifies the source file encoding for the compiler, overriding the matching value, if any, in JAVA$OPTIONS. Values are the same as for the javac -encoding option. If you do not specify an encoding on the command line or in JAVA$OPTIONS, then the encoding is assumed to be the value returned by:

System.getProperty("file.encoding");

This option is relevant only when loading a source file.

-fileout file

Displays all message to the designated file.

-force

Forces files to be loaded, even if they match digest table entries.

-genmissing

Determines what classes and methods are referred to by the classes that the loadjava tool is asked to process. Any classes not found in the database or file arguments are called missing classes. This option generates dummy definitions for missing classes containing all the referred methods. It then loads the generated classes into the database. This processing happens before the class resolution.

Because detecting references from source is more difficult than detecting references from class files, and because source is not generally used for distributing libraries, the loadjava tool will not attempt to do this processing for source files.

The schema in which the missing classes are loaded will be the one specified by the -user option, even when referring classes are created in some other schema. The created classes will be flagged so that tools can recognize them. In particular, this is needed, so that the verifier can recognize the generated classes.

-genmissingjar jar_file

This option performs the same actions as -genmissing. In addition, it creates a JAR file, jar_file, that contains the definitions of any generated classes.

-grant

Grants the EXECUTE privilege on loaded classes to the listed users. Any number and combination of user names can be specified, separated by commas, but not spaces.

Granting the EXECUTE privilege on an object in another schema requires that the original CREATE PROCEDURE privilege was granted with the WITH GRANT options.

Note:

  • -grant is a cumulative option. Users are added to the list of those with the EXECUTE privilege. To remove privileges, use the -cleargrants option.

  • The schema name should be used in uppercase.

-help

Displays usage message on how to use the loadjava tool and its options.

-jarasresource

Instead of unpacking the JAR file and loading each class within it, loads the whole JAR file into the schema as a resource.

-noaction

Take no action on the files. Actions include creating the schema objects, granting execute permissions, and so on. The normal use is within an option file to suppress creation of specific classes in a JAR. When used on the command line, unless overridden in the option file, it will cause the loadjava tool to ignore all files. Except that JAR files will still be examined to determine if they contain a META-INF/loadjava-options entry. If so, then the option file is processed. The -action option in the option file will override the -noaction option specified on the command line.

-norecursivejars

Treat JAR files contained in other JAR files as resources. This is the default behavior. This option is used to override the -recursivejars option.

-nosynonym

Do not create a public synonym for the classes. This is the default behavior. This overrides the -synonym option.

-nousage

Suppresses the usage message that is given if either no option is specified or if the -help option is specified.

-noverify

Causes the classes to be loaded without bytecode verification. oracle.aurora.security.JServerPermission(Verifier) must be granted to use this option. To be effective, this option must be used in conjunction with -resolve.

-oci | -oci8

Directs the loadjava tool to communicate with the database using the JDBC Oracle Call Interface (OCI) driver. -oci and -thin are mutually exclusive. If neither is specified, then -oci is used by default. Choosing -oci implies the syntax of the -user value. You do not need to provide the URL.

-publish package

The package is created or replaced by the loadjava tool. Wrappers for the eligible methods will be defined in this package. Through the use of option files, a single invocation of the loadjava tool can be instructed to create more than one package. Each package will undergo the same name transformations as the methods.

-pubmain number

A special case applied to methods with a single argument, which is of type java.lang.String[]. Multiple variants of the SQL procedure or function will be created, each of which takes a different number of arguments of type VARCHAR. In particular, variants are created taking all arguments up to and including number. The default value is 3. This option applies to main, as well as any method that has exactly one argument of type java.lang.String[].

-recursivejars

Normally, if the loadjava tool encounters an entry in a JAR with a .jar extension, it will load the entry as a resource. If this option is specified, then the loadjava tool will process contained JAR files as if they were top-level JAR files. That is, it will read their entries and load classes, sources, and resources.

-resolve

Compiles, if necessary, and resolves external references in classes after all classes on the command line have been loaded. If you do not specify the -resolve option, the loadjava tool loads files, but does not compile or resolve them.

-resolver

Specifies an explicit resolver specification, which is bound to the newly loaded classes. If -resolver is not specified, then the default resolver specification, which includes current user's schema and PUBLIC, is used.

-resolveonly

Causes the loadjava tool to skip the initial creation step. It will still perform grants, resolves, create synonyms, and so on.

-schema

Designates the schema where schema objects are created. If not specified, then the -user schema is used. To create a schema object in a schema that is not your own, you must have the following privileges:

  • CREATE TABLE or CREATE ANY TABLE

  • CREATE INDEX or CREATE ANY INDEX

  • SELECT ANY TABLE

  • UPDATE ANY TABLE

  • INSERT ANY TABLE

  • DELETE ANY TABLE

  • CREATE PROCEDURE or CREATE ANY PROCEDURE

  • ALTER ANY PROCEDURE

Finally, you must have the JServerPermission loadLibraryInClass for the class.

Note: The above-mentioned privileges allow the grantee to create and manipulate tables in any schema except the SYS schema. For security reasons, Oracle recommends that you use these settings only with great caution.

-stdout

Causes the output to be directed to stdout, rather than to stderr.

-stoponerror

Normally, if an error occurs while the loadjava tool is processing files, it will issue a message and continue to process other classes. This option stops when an error occurs. In addition, it reports all errors that apply to Java objects and are contained in the USER_ERROR table of the schema in which classes are being loaded. Except that is does not report ORA-29524 errors. These are errors that are generated when a class cannot be resolved, because a referred class could not be resolved. Therefore, these errors are a secondary effect of whatever caused a referred class to be unresolved.

-synonym

Creates a PUBLIC synonym for loaded classes making them accessible outside the schema into which they are loaded. To specify this option, you must have the CREATE PUBLIC SYNONYM privilege. If -synonym is specified for source files, then the classes compiled from the source files are treated as if they had been loaded with -synonym.

-tableschema schema

Creates the loadjava tool internal tables within the specified schema, rather than in the Java file destination schema.

-thin

Directs the loadjava tool to communicate with the database using the JDBC Thin driver. Choosing -thin implies the syntax of the -user value. You do need to specify the appropriate URL through the -user option.

-unresolvedok

When combined with -resolve, will ignore unresolved errors.

-user

Specifies a user name, password, and database connection string. The files will be loaded into this database instance.

-verbose

Directs the loadjava tool to display detailed status messages while running. Use the -verbose option to learn when the loadjava tool does not load a file, because it matches a digest table entry.

-jarsasdbobjects

Indicates that JARs processed by the current loadjava tool command are to be stored in the database as database resident JARs.

-prependjarnames

Is used with the -jarsasdbobjects option. This option enables classes with the same names coming from different JARs to coexist in the same schema. It does this by prefixing a version of the name of the JAR to the class name to produce a unique name for the database object.


Argument Details

This section describes the details of some of the loadjava tool arguments whose behavior is more complex than the summary descriptions contained in Table 11-2.

File Names

You can specify as many .class, .java, .sqlj, .jar, .zip, and resource files as you want and in any order. If you specify a JAR or ZIP file, then the loadjava tool processes the files in the JAR or ZIP. There is no JAR or ZIP schema object. If a JAR or ZIP contains another JAR or ZIP, the loadjava tool does not process them.

The best way to load files is to put them in a JAR or ZIP and then load the archive. Loading archives avoids the resource schema object naming complications. If you have a JAR or ZIP that works with the Java Development Kit (JDK), then you can be sure that loading it with the loadjava tool will also work, without having to learn anything about resource schema object naming.

Schema object names are different from file names, and the loadjava tool names different types of schema objects differently. Because class files are self-identifying, the mapping of class file names to schema object names done by the loadjava tool is invisible to developers. Source file name mapping is also invisible to developers. The loadjava tool gives the schema object the fully qualified name of the first class defined in the file. JAR and ZIP files also contain the names of their files.

However, resource files are not self identifying. The loadjava tool generates Java resource schema object names from the literal names you supply as arguments. Because classes use resource schema objects and the correct specification of resources is not always intuitive, it is important that you specify resource file names correctly on the command line.

The perfect way to load individual resource files correctly is to run the loadjava tool from the top of the package tree and specify resource file names relative to that directory.

Note:

The top of the package tree is the directory you would name in a CLASSPATH.

If you do not want to follow this rule, then observe the details of resource file naming that follow. When you load a resource file, the loadjava tool generates the resource schema object name from the resource file name, as literally specified on the command line. For example, if you type:

% cd /home/scott/javastuff
% loadjava options alpha/beta/x.properties
% loadjava options /home/scott/javastuff/alpha/beta/x.properties

Although you have specified the same file with a relative and an absolute path name, the loadjava tool creates two schema objects, alpha/beta/x.properties and ROOT/home/scott/javastuff/alpha/beta/x.properties. The name of the resource schema object is generated from the file name as entered.

Classes can refer to resource files relatively or absolutely. To ensure that the loadjava tool and the class loader use the same name for a schema object, enter the name on the command line, which the class passes to getResource() or getResourceAsString().

Instead of remembering whether classes use relative or absolute resource names and changing directories so that you can enter the correct name on the command line, you can load resource files in a JAR, as follows:

% cd /home/scott/javastuff
% jar -cf alpharesources.jar alpha/*.properties
% loadjava options alpharesources.jar

To simplify the process further, place both the class and resource files in a JAR, which makes the following invocations equivalent:

% loadjava options alpha.jar
% loadjava options /home/scott/javastuff/alpha.jar

The preceding loadjava tool commands imply that you can use any path name to load the contents of a JAR file. Even if you run the redundant commands, the loadjava tool would realize from the digest table that it need not load the files twice. This implies that reloading JAR files is not as time-consuming as it might seem, even when few files have changed between the different invocations of the loadjava tool.

definer

{-definer | -d}

This option is identical to the definer rights in stored procedures and is conceptually similar to the UNIX setuid facility. However, you can apply the -definer option to individual classes, in contrast to setuid, which applies to a complete program. Moreover, different definers may have different privileges. Because an application can consist of many classes, you must apply -definer with care to achieve the desired results. That is, classes run with the privileges they need, but no more.

noverify

[-noverify]

This option causes the classes to be loaded without bytecode verification. oracle.aurora.security.JServerPermission(Verifier) must be granted to run this option. Also, this option must be used in conjunction with -resolve.

The verifier ensures that incorrectly formed Java binaries cannot be loaded for running on the server. If you know that the JAR or classes you are loading are valid, then the use of this option will speed up the process associated with the loadjava tool. Some Oracle Database-specific optimizations for interpreted performance are put in place during the verification process. Therefore, the interpreted performance of your application may be adversely affected by using this option.

optionfile

[-optionfile <file>]

This option enables you to specify a file with different options that you can specify with the loadjava tool. This file is read and processed by the loadjava tool before any other loadjava tool options are processed. The file can contain one or more lines, each of which contains a pattern and a sequence of options. Each line must be terminated by a newline character (\n).

For each file or JAR entry that is processed by the loadjava tool, the long name of the schema object that is going to be created is checked against the patterns. Patterns can end in a wildcard (*) to indicate an arbitrary sequence of characters, or they must match the name exactly.

Options to be applied to matching Java schema objects are supplied on the rest of the line. Options are appended to the command-line options, they do not replace them. In case more than one line matches a name, the matching rows are sorted by length of pattern, with the shortest first, and the options from each row are appended. In general, the loadjava tool options are not cumulative. Rather, later options override earlier ones. This means that an option specified on a line with a longer pattern will override a line with a shorter pattern.

This file is parsed by a java.io.StreamTokenizer.

You can use Java comments in this file. A line comment begins with a #. Empty lines are ignored. The quote character is a double quote ("). That is, options containing spaces should be surrounded by double quotes. Certain options, such as -user and -verbose, affect the overall processing of the loadjava tool and not the actions performed for individual Java schema objects. Such options are ignored if they appear in an option file.

To help package applications, the loadjava tool looks for the META-INF/loadjava-options entry in each JAR it processes. If it finds such an entry, then it treats it as an options file that is applied for all other entries in the option file. However, the loadjava tool does some processing on entries in the order in which they occur in the JAR.

If the loadjava tool has partially processed entities before it processes META-INF/loadjava-options, then it attempts to patch up the schema object to conform to the applicable options. For example, the loadjava tool alters classes that were created with invoker rights when they should have been created with definer rights. The fix for -noaction is to drop the created schema object. This yields the correct effect, except that if a schema object existed before the loadjava tool started, then it would have been dropped.

publish

[-publish <package>]
[-pubmain <number>]

The publishing options cause the loadjava tool to create PL/SQL wrappers for methods contained in the processed classes. Typically, a user wants to publish wrappers for only a few classes in a JAR. These options are most useful when specified in an option file.

To be eligible for publication, the method must satisfy the following:

  • It must be a member of a public class.

  • It must be declared public and static.

  • The method signature should satisfy the following rules so that it can be mapped:

    • Java arithmetic types for arguments and return values are mapped to NUMBER.

    • char as an argument and return type is mapped to VARCHAR.

    • java.lang.String as an argument and return type is mapped to VARCHAR.

    • If the only argument of the method has type java.lang.String, special rules apply, as listed in the -pubmain option description.

    • If the return type is void, then a procedure is created.

    • If the return type is an arithmetic, char, or java.lang.String type, then a function is created.

Methods that take arguments or return types that are not covered by the preceding rules are not eligible. No provision is made for OUT and IN OUT SQL arguments, OBJECT types, and many other SQL features.

resolve

{-resolve | -r}

Use -resolve to force the loadjava tool to compile and resolve a class that has previously been loaded. It is not necessary to specify -force, because resolution is performed after, and independent of, loading.

resolver

{-resolver | -R} resolver_specification

This option associates an explicit resolver specification with the class schema objects that the loadjava tool creates or replaces.

A resolver specification consists of one or more items, each of which consists of a name specification and a schema specification expressed in the following syntax:

"((name_spec schema_spec) [(name_spec schema_spec)] ...)"

A name specification is similar to a name in an import statement. It can be a fully qualified Java class name or a package name whose final element is the wildcard character asterisk (*) or simply an asterisk (*). However, the elements of a name specification must be separated by slashes (/), not periods (.). For example, the name specification a/b/* matches all classes whose names begin with a.b. The special name * matches all class names.

A schema specification can be a schema name or the wildcard character dash (-). The wildcard does not identify a schema, but directs the resolve operation not to mark a class invalid, because a reference to a matching name cannot be resolved. Use dash (-) when you must test a class that refers to a class you cannot or do not want to load. For example, GUI classes that a class refers to but does not call, because when run in the server there is no GUI.

When looking for a schema object whose name matches the name specification, the resolution operation looks in the schema named by the partner schema specification.

The resolution operation searches schemas in the order in which the resolver specification lists them. For example,

-resolver '((* SCOTT) (* PUBLIC))'

This implies that search for any reference first in SCOTT and then in PUBLIC. If a reference is not resolved, then mark the referring class invalid and display an error message.

Consider the following example:

-resolver "((* SCOTT) (* PUBLIC) (my/gui/* -))"

This implies that search for any reference first in SCOTT and then in PUBLIC. If the reference is to a class in the package my.gui and is not found, then mark the referring class valid and do not display an error. If the reference is not to a class in my.gui and is not found, then mark the referring class invalid and produce an error message.

user

{-user | -u} user/password[@database_url]

By default, the loadjava tool loads into the logged in schema specified by the -user option. You use the -schema option to specify a different schema to load into. This does not require you to log in to that schema, but does require that you have sufficient permissions to alter the schema.

The permissible forms of @database_url depend on whether you specify -oci or -thin, as described:

  • -oci:@database_url is optional. If you do not specify, then the loadjava tool uses the user's default database. If specified, database_url can be a TNS name or an Oracle Net Services name-value list.

  • -thin:@database_url is required. The format is host:lport:SID.

    where:

    • host is the name of the computer running the database.

    • lport is the listener port that has been configured to listen for Oracle Net Services connections. In a default installation, it is 5521.

    • SID is the database instance identifier. In a default installation, it is ORCL.

The following are examples of the loadjava tool commands:

  • Connect to the default database with the default OCI driver, load the files in a JAR into the TEST schema, and then resolve them:

    loadjava -u joe -resolve -schema TEST ServerObjects.jar
    Password: password
    
  • Connect with the JDBC Thin driver, load a class and a resource file, and resolve each class:

    loadjava -thin -u SCOTT@dbhost:5521:orcl \
      -resolve alpha.class beta.props
    Password: password
    
  • Add Betty and Bob to the users who can run alpha.class:

    loadjava -thin -schema test -u SCOTT@localhost:5521:orcl \
      -grant BETTY,BOB alpha.class
    Password: password
    
    

jarsasdbobjects

This option indicates that JARs processed by the current loadjava tool are to be stored in the database along with the classes they contain, and knowledge of the association between the classes and the JAR is to be retained in the database. In other words, this argument indicates that the JARs processed by the current loadjava tool are to be stored in the database as database resident JARs.

prependjarnames

This option is used with the -jarsasdbobjects option. This option enables classes with the same names coming from different JARs to coexist in the same schema.

The dropjava Tool

The dropjava tool is the converse of the loadjava tool. It transforms command-line file names and JAR or ZIP file contents to schema object names, drops the schema objects, and deletes their corresponding digest table rows. You can enter .java, .class, .sqlj, .ser, .zip, .jar, and resource file names on the command line and in any order.

Alternatively, you can specify a schema object name directly to the dropjava tool. A command-line argument that does not end in .jar, .zip, .class, .java, or .sqlj is presumed to be a schema object name. If you specify a schema object name that applies to multiple schema objects, then all will be removed.

Dropping a class invalidates classes that depend on it, recursively cascading upwards. Dropping a source drops classes derived from it.

Note:

You must remove Java schema objects in the same way that you first loaded them. If you load a .sqlj source file and translate it in the server, then you must run the dropjava tool on the same source file. If you translate on a client and load classes and resources directly, then run the dropjava tool on the same classes and resources.

You can run the dropjava tool either from the command line or by using the dropjava method in the DBMS_JAVA class. To run the dropjava tool from within your Java application, use the following command:

call dbms_java.dropjava('... options...');

The options are the same as specified on the command line. Separate each option with a space. Do not separate the options using commas. The only exception to this is the -resolver option. The connection is always made to the current session. Therefore, you cannot specify another user name through the -user option.

For -resolver, you should specify all other options first, a comma (,), then the -resolver option with its definition. Do not specify the -thin, -oci, -user, and -password options, because they relate to the database connection for the loadjava tool. The output is directed to stderr. Set serveroutput on and call dbms_java.set_output, as appropriate.

This section covers the following topics:

Syntax

The syntax of the dropjava tool command is:

dropjava [options] {file.java | file.class | file.sqlj | 
file.jar | file.zip | resourcefile} ...
  -u | -user user/[password][@database]
  [-genmissingjar JARfile]
  [-jarasresource]
  [-o | -oci | -oci8]
  [-optionfile file]
  [-S | -schema schema]
  [-stdout]
  [-s | -synonym]
  [-t | -thin]
  [-v | -verbose]

Argument Summary

Table 11-3 summarizes the dropjava tool arguments.

Table 11-3 dropjava Argument Summary

Argument Description

-user

Specifies a user name, password, and optional database connection string. The files will be dropped from this database instance.

filenames

Specifies any number and combination of .java, .class, .sqlj, .ser, .jar, .zip, and resource file names.

-genmissingjar JARfile

Treats the operand of this option as a file to be processed.

-jarasresource

Drops the whole JAR file, which was previously loaded as a resource.

-oci | -oci8

Directs the dropjava tool to connect with the database using the OCI JDBC driver. The -oci and the -thin options are mutually exclusive. If neither is specified, then the -oci option is used by default. Choosing the -oci option implies the form of the -user value.

-optionfile file

Has the same usage as for the loadjava tool.

-schema schema

Designates the schema from which schema objects are dropped. If not specified, then the logon schema is used. To drop a schema object from a schema that is not your own, you need the DROP ANY PROCEDURE and UPDATE ANY TABLE privileges.

-stdout

Causes the output to be directed to stdout, rather than to stderr.

-synonym

Drops a PUBLIC synonym that was created with the loadjava tool.

-thin

Directs the dropjava tool to communicate with the database using the JDBC Thin driver. Choosing the -thin option implies the form of the -user value.

-verbose

Directs the dropjava tool to emit detailed status messages while running.

–list

Drops the classes, Java source, or resources listed on the command line without them being present on the client machine or server machine.

-listfile

Reads a file and drops the classes, Java source, or resources listed in the file without them being present on the client machine or server machine.The file contains the internal representation of the complete class, Java source, or resource name one per line.


Argument Details

This section describes a few of the dropjava tool arguments, which are complex.

File Names

The dropjava tool interprets most file names as the loadjava tool does:

  • .class files

    Finds the class name in the file and drops the corresponding schema object.

  • .java and .sqlj files

    Finds the first class name in the file and drops the corresponding schema object.

  • .jar and .zip files

    Processes the archived file names as if they had been entered on the command line.

If a file name has another extension or no extension, then the dropjava tool interprets the file name as a schema object name and drops all source, class, and resource objects that match the name.

If the dropjava tool encounters a file name that does not match a schema object, then it displays a message and processes the remaining file names.

user

{-user | -u} user/password[@database]

The permissible forms of @database depend on whether you specify -oci or -thin:

  • -oci:@database is optional. If you do not specify, then the dropjava tool uses the user's default database. If specified, then database can be a TNS name or an Oracle Net Services name-value list.

  • -thin:@database is required. The format is host:lport:SID.

    where:

    • host is the name of the computer running the database.

    • lport is the listener port that has been configured to listen for Oracle Net Services connections. In a default installation, it is 5521.

    • SID is the database instance identifier. In a default installation, it is ORCL.

The following are examples of the dropjava tool command:

  • Drop all schema objects in the TEST schema in the default database that were loaded from ServerObjects.jar:

    dropjava -u SCOTT -schema TEST ServerObjects.jar
    Password: password
    
  • Connect with the JDBC Thin driver, then drop a class and a resource file from the user's schema:

    dropjava -thin -u SCOTT@dbhost:5521:orcl alpha.class beta.props
    Password: password
    

List Based Deletion

Earlier versions of the dropjava tool required that the classes, JARs, source, and resources be present on the machine, where the client or server side utility is running. The current version of dropjava has an option that enables you to drop classes, resources, or sources based on a list of classes, which may not exist on the client machine or the server machine. This list can be either on the command line or in a text file. For example:

dropjava –list –u scott –v this.is.my.class this.is.your.class
Password: password

The preceding command drops the classes this.is.my.class and this.is.your.class listed on the command line without them being present on the client machine or server machine.

dropjava –listfile my.list –u scott –s –v
Password: password

The preceding command drops classes, resources, or sources and their synonyms based on a list of classes listed in my.list and displays verbosely.

Dropping Resources

Care must be taken if you are removing a resource that was loaded directly into the server. This includes profiles, if you translated them on the client without using the -ser2class option. When dropping source or class schema objects or resource schema objects that were generated by the server-side SQLJ translator, the schema objects will be found according to the package specification in the applicable .sqlj source file. However, the fully qualified schema object name of a resource that was generated on the client and loaded directly into the server depends on path information in the .jar file or that specified on the command line at the time you loaded it. If you use a .jar file to load resources and use the same .jar file to remove resources, then there will be no problem. However, if you use the command line to load resources, then you must be careful to specify the same path information when you run the dropjava tool to remove the resources.

The ojvmjava Tool

The ojvmjava tool is an interactive interface to the session namespace of a database instance. You specify database connection arguments when you start the ojvmjava tool. It then presents you with a prompt to indicate that it is ready for commands.

The shell can launch an executable, that is, a class with a static main() method. This is done either by using the command-line interface or by calling a database resident class. If you call a database resident class, the executable must be loaded with the loadjava tool.

This section covers the following topics:

Syntax

The syntax of the ojvmjava tool command is:

ojvmjava {-user user[/password@database ] [options]
  [@filename]
  [-batch]
  [-c | -command command args]
  [-debug]
  [-d | -database conn_string]
  [-fileout filename]
  [-o | -oci | -oci8]
  [-oschema schema]
  [-t | -thin]
  [-version | -v]
 -runjava [server_file_system]
 -jdwp port [host]
 -verbose

Argument Summary

Table 11-4 summarizes the ojvmjava tool arguments.

Table 11-4 ojvmjava Argument Summary

Argument Description

-user | -u

Specifies user name for connecting to the database. This name is not case-sensitive. The name will always be converted to uppercase. If you provide the database information, then the default syntax used is OCI. You can also specify the default database.

-password | -p

Specifies the password for connecting to the database. This is not case-sensitive and will always be converted to uppercase.

@filename

Specifies a script file that contains the ojvmjava tool commands to be run.

-batch

Disables all messages displayed to the screen. No help messages or prompts will be displayed. Only responses to commands entered are displayed.

-command

Runs the desired command. If you do not want to run the ojvmjava tool in interpretive mode, but only want to run a single command, then run it with this option followed by a string that contains the command and the arguments. Once the command runs, the ojvmjava tool exits.

-debug

Displays debugging information.

-d | -database conn_string

Provide a database connection string.

-fileout file

Redirect output to the provided file.

-o | -oci | -oci8

Uses the JDBC OCI driver. The OCI driver is the default. This flag specifies the syntax used in either the @database or -database option.

-o schema schema

Uses this schema for class lookup.

-t | -thin

Specifies that the database syntax used is for the JDBC Thin driver. The database connection string must be of the form host:port:SID or an Oracle Net Services name-value list.

-verbose

Displays the connection information.

-version

Shows the version.

-runjava

Uses DBMS_JAVA.runjava when executing Java commands. With no argument, interprets -classpath as referring to the client file system. With argument server_file_system interprets -classpath as referring to the file system on which Oracle server is running, as DBMS_JAVA.runjava normally does.

-jdwp

Makes the connection listen for a debugger connection on the indicated port and host. The default value of host is localhost.


Example

Open a shell on the session namespace of the database orcl on listener port 2481 on the host dbserver, as follows:

ojvmjava -thin -user SCOTT@dbserver:2481:orcl
Password: password

Functionality

The ojvmjava tool commands span several different types of functionality, which are grouped as follows:

ojvmjava Tool Command-Line Options

This section describes the options for the ojvmjava tool command.

The ojvmjava Tool Output Redirection

You can direct any output generated by the ojvmjava tool to a file by appending &>filename at the end of the command options. The following command directs all output to the listDir file:

ls -lR &>/tmp/listDir

Scripting the ojvmjava Tool Commands in the @filename Option

This @filename option designates a script file that contains one or more ojvmjava tool commands. The script file specified is located on the client. The ojvmjava tool reads the file and runs all commands on the designated server. In addition, because the script file is run on the server, any interaction with the operating system in the script file, such as redirecting output to a file or running another script, will occur on the server. If you direct the ojvmjava tool to run another script file, then this file must exist in $ORACLE_HOME on the server.

Enter the ojvmjava tool command followed by any options and any expected input arguments.

The script file contains the ojvmjava tool command followed by options and input parameters. The input parameters can be passed to the ojvmjava tool on the command line. The ojvmjava tool processes all known options and passes on any other options and arguments to the script file.

To access arguments within the commands in the script file, use &1...&n to denote the arguments. If all input parameters are passed to a single command, then you can type &* to denote that all input parameters are to be passed to this command.

The following shows the contents of the script file, execShell:

chmod +x SCOTT nancy /alpha/beta/gamma
chown SCOTT /alpha/beta/gamma
java hello.World &*

Because only two input arguments are expected, you can implement the Java command input parameters, as follows:

java hello.World &1 &2

Note:

You can also supply arguments to the -command option in the same manner. The following shows an example:
ojvmjava ... -command "cd &1" contexts

After processing all other options, the ojvmjava tool passes contexts as argument to the cd command.

To run this file, do the following:

ojvmjava -user SCOTT -thin -database dbserver:2481:orcl \
  @execShell alpha beta
Password: password

The ojvmjava tool processes all options that it knows about and passes along any other input parameters to be used by the commands that exist within the script file. In this example, the parameters, alpha and beta, are passed to the java command in the script file. The actual command is run as follows:

java hello.World alpha beta

You can add any comments in your script file using hash (#). Comments are ignored by the ojvmjava tool. For example:

#this whole line is ignored by ojvmjava

-runjava

This option controls whether or not the ojvmjava tool shell command Java runs executable classes using the command-line interface or database resident classes. When the -runjava option is present the command-line interface is used. Otherwise, the executable must be a database resident class that was previously loaded with the loadjava tool. Using the optional argument server_file_system means that the -classpath terms are on the file system of the machine running Oracle server. Otherwise, they are interpreted as being on the file system of the machine running the ojvmjava tool.

-jdwp

This option specifies a debugger connection to listen for when the shell command java is used to run an executable. This allows for debugging the executable. The arguments specify the port and host. The default value of the host argument is localhost. These are used to execute a call to DBMS_DEBUG_JDWP.CONNECT_TCP from the RDBMS session, in which the executable is run.

Running sess_sh Within Applications

You can run sess_sh commands from within a Java or PL/SQL application using the following commands:

Application Type Command and Description
PL/SQL applications
dbms_namespace.shell(in command VARCHAR2)
Your application can run individual commands on a unique session instance. The state of the shell is preserved between different calls of sess_sh within the same session. The following examples run the cd command of the sess_sh tool within a PL/SQL application:
dbms_namespace.shell('cd /webdomains');

dbms_namespace.shell('ls &> /tmp/test');

To reset the state of the shell instance, run the exit command, as follows:

dbms_namespace.shell('exit');
Java applications Instantiates oracle.aurora.namespace.shell.Shell within a Java server object. After creation, you must initialize the Shell object using its initialize method. Once initialized, you can run sess_sh commands, as follows:
 String commands="cd /webdomains\nls -l";
 StringReader commandReader = new StringReader(commands);
 Shell sh = new oracle.aurora.namespace.shell.Shell();

 try
 {
   sh.initialize();
   sh.invoke(new BufferedReader(commandReader), false);
 }
 catch (ToolsException te)
 {
   //Error executing the commands
 }

Shell Commands

This section describes the following commands available within the ojvmjava shell:

Note:

An error is reported if you enter an unsupported command.

Table 11-5 summarizes the commands that share one or more common options, which are summarized in Table 11-5:

Table 11-5 ojvmjava Command Common Options

Option Description

-describe | -d

Summarizes the operation of the tool.

-help | -h

Summarizes the syntax of the tool.

-version

Shows the version.


echo

This command displays to stdout exactly what is indicated. This is used mostly in script files.

The syntax is as follows:

echo [echo_string] [args]

echo_string is a string that contains the text you want written to the screen during the shell script invocation and args are input arguments from the user. For example, the following command displays out a notification:

echo "Adding an owner to the schema" &1

If the input argument is SCOTT, then the output would be:

Adding an owner to the schema SCOTT

exit

This command terminates ojvmjava. The syntax is as follows:

exit

For example, to leave a shell, use the following command:

$ exit
%

help

This command summarizes the syntax of the shell commands. You can also use the help command to summarize the options for a particular command. The syntax is as follows:

help [command]

java

This command is analogous to the JDK java command. It calls the static main() method of a class. It does this either by using the command-line interface or using a database resident class, depending on the setting of the runjava mode. In the latter case, the class must have been previously loaded with the loadjava tool. The command provides a convenient way to test Java code that runs in the database. In particular, the command catches exceptions and redirects the standard output and standard error of the class to the shell, which displays them as with any other command output. The destination of standard out and standard error for Java classes that run in the database is one or more database server process trace files, which are inconvenient and may require DBA privileges to read.

The syntax of the command with runjava mode off is:

java [-schema schema] class [arg1 ... argn]

The syntax of the command with runjava mode on is:

java [command-line options] class [arg1 ... argn]

where, command-line options can be any of those mentioned in Table 3-1.

Table 11-6 summarizes the arguments of this command.

Table 11-6 java Argument Summary

Argument Description

class

Names the Java class schema object that is to be run.

-schema

Names the schema containing the class to be run. The default is the invoker's schema. The schema name is case-sensitive.

arg1 ... argn

Arguments to the static main() method of the class.


Consider the following Java file, World.java:

package hello;
public class World
{
  public World()
  {
    super();
  }

  public static void main(String[] argv)
  {
    System.out.println("Hello from Oracle Database");
    if (argv.length != 0)
      System.out.println("You supplied " + argv.length + " arguments: ");
    for (int i = 0; i < argv.length; i++)
      System.out.println(" arg[" + i + "] : " + argv[i]);
  }
}

You can compile, load, publish, and run the class, as follows:

% javac hello/World.java

% loadjava -r -user SCOTT@localhost:2481:orcl hello/World.class
Password: password
% ojvmjava -user SCOTT -database localhost:2481:orcl
Password: password
$ java hello.World alpha beta
Hello from Oracle Database
You supplied 2 arguments:
arg[0] : alpha
arg[1] : beta

version

This command shows the version of the ojvmjava tool. You can also show the version of a specified command. The syntax of this command is:

version [options] [command]

For example, you can display the version of the shell, as follows:

$ version
1.0

whoami

This command displays the user name of the user who logged in to the current session. The syntax of the command is:

whoami

connect

This command enables the client to drop the current connection and connect to different databases without having to reinvoke the ojvmjava tool with a different connection description.

The syntax of this command is:

connect [-service service] [-user user][-password password]

You can use this command as shown in the following examples:

connect -s thin@locahost:5521:orcl -u scott/tiger
connect -s oci@locahost:5521:orcl -u scott -p tiger

Table 11-7 summarizes the arguments of this command.

Table 11-7 connect Argument Summary

Argument Description

-service | -s

Any valid JDBC driver URLS, namely, oci @<connection descriptor> and thin@<host:port:db>

-user | -u

User to connect as

-password | -p

Password to connect with


runjava

This command queries or modifies the runjava mode. The runjava mode determines whether or not the java command uses the command-line interface to run executables. The java command:

  • Uses the command-like interface when runjava mode is on

  • Uses database resident executables when runjava mode is off

Using the runjava command with no arguments displays the current setting of runjava mode.

Table 11-8 summarizes the arguments of this command.

Table 11-8 runjava Argument Summary

Argument Description

off

Turns runjava mode off.

on

Turns runjava mode on.

server_file_system

Turns runjava mode on. Using this option means that -classpath terms are on the file system of the machine running Oracle server. Otherwise, they are interpreted as being on the file system of the machine running the ojvmjava tool.


jdwp

This command queries or modifies whether and how a debugger connection is listened for when an executable is run by the Java command.

Note:

The RDBMS session, prior to starting the executable, executes a DBMS_DEBUG_JDWP.CONNECT_TCP call with the specified port and host. This is called Listening.

Using this command with no arguments displays the current setting.

Table 11-9 summarizes the arguments of this command.

Table 11-9 jdwp Argument Summary

Argument Description

off

Stops listening in future executables.

port

Enables listening and specifies the port to be used.

host

Enables listening and specifies the host to be used. The default value for this argument is localhost.