Where to download jdk1.5.0 ?
since from this https://forums.oracle.com/thread/2269694 page it is said as Oracle 11 + JDK1.5 will work
First - you don't need Java 1.5 in order to do what you are trying to do.
Oracle 11g versions use Java 1.5 internally so you have two other options:
1. Load the Java source, not precompiled class files. That way the internal Oracle Java will compile it.
2. Use the '-target' command-line parameter for 'javac' when you compile the source and specify Java 1.5. That will create the proper class file versions for loading into the DB.
It is easier to load the Java source so that you don't have to worry about the correct class file format being used. But you still can't reference classes that did not exist in Java 1.5.
You can download any available Java version from the main Java SE Downloads page
Just use the 'Previous Releases' button to go to the page that lists the older versions.