Class LazyLoading

test/LazyLoading.java:5–183

import java.io.IOException;

public class LazyLoading {
  public static boolean loadLazy;

  public static void expect(boolean v) {
    if (! v) throw new RuntimeException();
  }

  private static File findClass(String name, File directory) {
    for (File file: directory.listFiles()) {
      if (file.isFile()) {
        if (file.getName().equals(name + ".class")) {
          return file;
        }
      } else if (file.isDirectory()) {
        File result = findClass(name, file);
        if (result != null) {
          return result;
        }
      }
    }
    return null;
  }

  private static byte[] read(File file) throws IOException {
    byte[] bytes = new byte[(int) file.length()];
    FileInputStream in = new FileInputStream(file);
    try {
      if (in.read(bytes) != (int) file.length()) {
        throw new RuntimeException();
      }
      return bytes;
    } finally {
      in.close();
    }
  }

  public static void main(String[] args) throws Exception {
    Class c = new MyClassLoader(LazyLoading.class.getClassLoader()).loadClass
      ("LazyLoading$Test");

    c.getMethod("test").invoke(null);
  }

  private static class MyClassLoader extends ClassLoader {
    public MyClassLoader(ClassLoader parent) {
      super(parent);
    }

    protected Class findClass(String name) throws ClassNotFoundException {
      try {
        return defineClass
          (name, read
           (LazyLoading.findClass
            (name, new File(System.getProperty("user.dir")))));
      } catch (IOException e) {
        throw new RuntimeException(e);
      }
    }