Special Features of Java Classes in the Database

This section describes features of Java classes when used in the database.

• How to Call the Main Method
  You typically start Java applications (outside the database) by running the Java VM on a class that has a main method.
• Threads in Java Applications
  With features of the java.lang.Thread package, you can use multiple threads in a Java application.
• No Such Method Exception
  If you supply an incorrect number of arguments when calling a Java method, or if you use an incorrect data type, the Java VM responds with a java.lang.NoSuchMethodException error. Check the number and type of arguments.
• How to Return Result Sets from Java Methods
  Write a Java method that returns a result set to the calling environment, and wrap this method in a SQL stored procedure declared to be EXTERNAL NAME of LANGUAGE JAVA.
• Values Returned from Java Via Stored Procedures
  You can use stored procedures created using the EXTERNAL NAME LANGUAGE JAVA as wrappers around Java methods. This section describes how to write your Java method to exploit OUT or INOUT parameters in the stored procedure.
• Security Management for Java
  Java provides security managers that you can use to control user access to security-sensitive features of your applications, such as file access and network access. You should take advantage of the security management features supported by your Java VM.