How do you dynamically compile and load external java classes? [duplicate]

Answer 1

I suggest using the Java Runtime Compiler library. You can give it a String in memory and it will compile and load the class into the current class loader (or one of your choice) and return the Class loaded. Nested classes are also loaded. Note: this works entirely in memory by default.

e.g.

 // dynamically you can call
 String className = "mypackage.MyClass";
 String javaCode = "package mypackage;\n" +
                  "public class MyClass implements Runnable {\n" +
                  "    public void run() {\n" +
                  "        System.out.println(\"Hello World\");\n" +
                  "    }\n" +
                  "}\n";
 Class aClass = CompilerUtils.CACHED_COMPILER.loadFromJava(className, javaCode);
 Runnable runner = (Runnable) aClass.newInstance();
 runner.run();