sketch a few more classpath classes

classpath/java/lang/ThreadLocal.java

@@ -0,0 +1,36 @@
+package java.lang;
+
+import java.util.Map;
+
+public class ThreadLocal<T> {
+  private static final Object Null = new Object();
+
+  protected T initialValue() {
+    return null;
+  }
+
+  public T get() {
+    Map<ThreadLocal, Object> map = Thread.currentThread().locals();
+    Object o = map.get(this);
+    if (o == null) {
+      o = initialValue();
+      if (o == null) {
+        o = Null;
+      }
+      map.put(this, o);
+    }
+    if (o == Null) {
+      o = null;
+    }
+    return (T) o;
+  }
+
+  public void set(T value) {
+    Map<ThreadLocal, Object> map = Thread.currentThread().locals();
+    Object o = value;
+    if (o == null) {
+      o = Null;
+    }
+    map.put(this, o);
+  }
+}