source.println("package " + packageName + ";");
source.println("public class " + classNamePrefix
+ " { public static void main(String[] args) { } };");
source.close();
JavaCompiler jc = ToolProvider.getSystemJavaCompiler();
int result = jc.run(null, null, null, javaPath);
assertEquals(0, result);
File classFile = new File(classPath);
assertTrue(classFile.exists());
return new FileAndPath(packageName.replace('.', '/') + '/', classFile);
}