Added several useful classes

classpath/java/io/ByteArrayInputStream.java

@@ -0,0 +1,25 @@
+package java.io;
+
+public class ByteArrayInputStream extends InputStream {
+  private final byte[] array;
+  private int position;
+  private final int length;
+
+  public ByteArrayInputStream(byte[] array, int offset, int length) {
+    this.array = array;
+    position = offset;
+    this.length = length;
+  }
+
+  public int read() {
+    if (position < length) {
+      return array[position++] & 0xff;
+    } else {
+      return -1;
+    }
+  }
+
+  public int available() {
+    returns length - position;
+  }
+}

classpath/java/lang/Enum.java

@@ -0,0 +1,38 @@
+package java.lang;
+
+import java.lang.reflect.Method;
+
+public abstract class Enum<E extends Enum<E>> {
+  private final String name;
+  private final int ordinal;
+
+  public Enum(String name, int ordinal) {
+    this.name = name;
+    this.ordinal = ordinal;
+  }
+
+  public int compareTo(E other) {
+    return ordinal - other.ordinal;
+  }
+
+  public static <T extends Enum<T>> T valueOf(Class<T> enumType, String name) {
+    if (name != null) {
+      try {
+        Method method = enumType.getMethod("values");
+        Enum values[] = (Enum[])(method.invoke(null));
+        for (Enum value : values) {
+          if (name.equals(value.name)) {
+            return (T) value;
+          }
+        }
+      } catch (Exception ex) {
+        throw new RuntimeException(ex);
+      }
+    }
+    return null;
+  }
+
+  public int ordinal() {
+    return ordinal;
+  }
+}

classpath/java/lang/IncompatibleClassChangeError.java

@@ -0,0 +1,11 @@
+package java.lang;
+
+public class IncompatibleClassChangeError extends LinkageError {
+  public IncompatibleClassChangeError(String message) {
+    super(message);
+  }
+
+  public IncompatibleClassChangeError() {
+    super();
+  }
+}

classpath/java/lang/NoSuchFieldError.java

@@ -0,0 +1,11 @@
+package java.lang;
+
+public class NoSuchFieldError extends IncompatibleClassChangeError {
+  public NoSuchFieldError(String message) {
+    super(message);
+  }
+
+  public NoSuchFieldError() {
+    super();
+  }
+}

classpath/java/lang/annotation/Annotation.java

@@ -0,0 +1,4 @@
+package java.lang.annotation;
+
+public interface Annotation {
+}

classpath/java/util/Comparator.java

@@ -0,0 +1,5 @@
+package java.util;
+
+public interface Comparator<T> {
+  public int compare(T o1, T o2);
+}

classpath/java/util/Date.java

@@ -0,0 +1,17 @@
+package java.util;
+
+public class Date {
+  public final long when;
+
+  public Date() {
+    when = System.currentTimeMillis();
+  }
+
+  public Date(long when) {
+    this.when = when;
+  }
+
+  public long getTime() {
+    return when;
+  }
+}