How to create a runnable jar file from source code programmatically?

Question

I need to create runnable .jar file programmatically from a string. My decision is to create a .class file from string and add it to the .jar using JarOutputStream.

1. What API must I use to create the .class file?
2. Are there any other solutions to create a .jar from the source code?

Answer 1

In order to do that, you can use the Java Compiler API.

There is this excellent tutorial that can walk you through.

Answer 2

To compile code, you need a compiler. You can either use the SunOracle compiler or the Eclipse compiler. Calling the compiler API (both have documented APIs) will produce a .class file in a temporary location. You can then make a jar.

For an example of this sort of thing, start with, for example, the Maven Compiler Plugin, which is a Java module which uses the compiler API. You'll have to find your way into the Plexus compiler module.