how is java platform independent? is jsp thread safe? what is mean by thread safe?
The concept of Write-once-run-anywhere (known as the Platform independent) is one of the important key feature of java language that makes java as the most powerful language.
When Java Code is compiled a byte code is generated which is independent of the system. This byte code is fed to the JVM (Java Virtual Machine) which resides in the system. Since every system has its own JVM, it doesn't matter where you compile the source code. The byte code generated by the compiler can be interpreted by any JVM of any machine. Hence it is called Platform independent Language.
JSP's are not thread safe by default but you can make it thread safe.Thread Safe is used to send only one client request for processing. It is used to implement Single Thread Model interface.