NullPointerException #24

 `System.setProperty("java.home", "C:\\Program Files\\Java\\jdk-11.0.1");
	StringBuilder sourceCode = new StringBuilder();
	sourceCode.append("package me.Perzan.compileString;\n");
	sourceCode.append("class HelloClass {\n");
	sourceCode.append(" public static void hello() { System.out.println(\"hello\"); }");
	sourceCode.append("}");
	InMemoryJavaCompiler compiler = InMemoryJavaCompiler.newInstance();
	
	compiler.addSource("HelloClass", sourceCode.toString());
	
	
	
	Map<String, Class<?>> classMap = compiler.compileAll();
	
	Class<?> helloClass = classMap.get("HelloClass");
	Method m = helloClass.getMethod("hello");
	
	m.invoke(null);`