История изменений

        var javaCompiler = ToolProvider.getSystemJavaCompiler();
        var fileManager = javaCompiler.getStandardFileManager(null, ENGLISH, UTF_8);
        var fileSystem = Jimfs.newFileSystem(Configuration.unix());
        var evalString = "k1 = \"test\"; k2 = \"tset\";";
        Files.writeString(fileSystem.getPath("/Example.java"), "" +
                "public class Example implements Runnable {" +
                "    public String k1, k2;" +
                "    public void run() {" +
                "        " + evalString + "" +
                "    }" +
                "}");
        var sources = fileManager.getJavaFileObjects(fileSystem.getPath("/Example.java"));
        javaCompiler.getTask(null, fileManager, null, null, null, sources).call();
        var bytecode = Files.readAllBytes(fileSystem.getPath("/Example.class"));
        var classLoader = new ClassLoader() {
            @Override
            protected Class<?> findClass(String name) throws ClassNotFoundException {
                if (name.equals("Example")) {
                    return defineClass(name, bytecode, 0, bytecode.length);
                }
                return super.findClass(name);
            }
        };
        var exampleClass = classLoader.findClass("Example");
        var exampleObj = (Runnable) exampleClass.getConstructor().newInstance();
        exampleObj.run();
        System.out.println(exampleClass.getField("k1").get(exampleObj));

        var javaCompiler = ToolProvider.getSystemJavaCompiler();
        var fileManager = javaCompiler.getStandardFileManager(null, ENGLISH, UTF_8);
        var fileSystem = Jimfs.newFileSystem(Configuration.unix());
        var evalString = "k1 = \"test\"; k2 = \"tset\";";
        Files.writeString(fileSystem.getPath("/Example.java"), "" +
                "public class Example implements Runnable {" +
                "    public String k1, k2;" +
                "    public void run() {" +
                "        " + evalString + "" +
                "    }" +
                "}");
        var sources = fileManager.getJavaFileObjects(fileSystem.getPath("/Example.java"));
        javaCompiler.getTask(null, fileManager, null, null, null, sources).call();
        var bytecode = Files.readAllBytes(fileSystem.getPath("/Example.class"));
        var classLoader = new ClassLoader() {
            @Override
            protected Class<?> findClass(String name) throws ClassNotFoundException {
                if (name.equals("Example")) {
                    return defineClass(name, bytecode, 0, bytecode.length);
                }
                return super.findClass(name);
            }
        };
        var exampleClass = classLoader.findClass("Example");
        var exampleObj = (Runnable) exampleClass.getConstructor().newInstance();
        exampleObj.run();
        System.out.println(exampleClass.getField("k1").get(exampleObj));