diff --git a/classes/java/lang/Boolean.java b/classes/java/lang/Boolean.java
index 6985d20..d56bfa0 100644
--- a/classes/java/lang/Boolean.java
+++ b/classes/java/lang/Boolean.java
@@ -1,4 +1,54 @@
 package java.lang;
 
-class Boolean {
+class Boolean
+    implements Comparable<Boolean> {
+    public static final Boolean FALSE = new Boolean(false);
+
+    public static final Boolean TRUE = new Boolean(true);
+
+    private final boolean value;
+
+    public Boolean(boolean value) {
+        this.value = value;
+    }
+
+    public Boolean(String s) {
+        this(parseBoolean(s));
+    }
+
+    public boolean booleanValue() {
+        return value;
+    }
+
+    public int compareTo(Boolean b) {
+        return value == b.value ? 0 : (value ? 1 : -1);
+    }
+
+    public boolean equals(Object obj) {
+        return (obj instanceof Boolean) && (value == ((Boolean)obj).booleanValue());
+    }
+
+    public int hashCode() {
+        return value ? 1231 : 1237;
+    }
+
+    public static boolean parseBoolean(String s) {
+        return "true".equalsIgnoreCase(s) ? true : false;
+    }
+
+    public String toString() {
+        return String.valueOf(value);
+    }
+
+    public static String toString(boolean b) {
+        return String.valueOf(b);
+    }
+
+    public static Boolean valueOf(boolean b) {
+        return (b ? TRUE : FALSE);
+    }
+
+    public static Boolean valueOf(String s) {
+        return parseBoolean(s) ? TRUE : FALSE;
+    }
 }
diff --git a/classes/java/lang/Byte.java b/classes/java/lang/Byte.java
index e26ae86..cee6b7a 100644
--- a/classes/java/lang/Byte.java
+++ b/classes/java/lang/Byte.java
@@ -1,4 +1,102 @@
 package java.lang;
 
-class Byte {
+public final class Byte
+    extends Number
+    implements Comparable<Byte> {
+
+    public static final byte MAX_VALUE = 127;
+
+    public static final byte MIN_VALUE = -128;
+
+    public static final int SIZE = 8;
+
+    private final byte value;
+
+    public Byte(byte value) {
+        this.value = value;
+    }
+
+    public Byte(String s) throws NumberFormatException {
+        this.value = parseByte(s, 10);
+    }
+
+    public byte byteValue() {
+        return this.value;
+    }
+
+    public int compareTo(Byte anotherByte) {
+        return this.value - anotherByte.value;
+    }
+
+    public static Byte decode(String nm)
+        throws NumberFormatException {
+        int i = Integer.decode(nm);
+        if (i < MIN_VALUE || i > MAX_VALUE)
+            throw new NumberFormatException();
+        return new Byte((byte)i);
+    }
+
+    public double doubleValue() {
+        return (double)value;
+    }
+
+    public boolean equals(Object obj) {
+        return obj instanceof Byte && value == ((Byte)obj).value;
+    }
+
+    public float floatValue() {
+        return (float)value;
+    }
+
+    public int hashCode() {
+        return value;
+    }
+
+    public int intValue() {
+        return (int)value;
+    }
+
+    public long longValue() {
+        return (long)value;
+    }
+
+    public static byte parseByte(String s)
+        throws NumberFormatException {
+        return parseByte(s, 10);
+    }
+
+    public static byte parseByte(String s,
+                                 int radix)
+        throws NumberFormatException {
+        int i = Integer.parseInt(s, radix);
+        if (i < MIN_VALUE || i > MAX_VALUE)
+            throw new NumberFormatException();
+        return (byte)i;
+    }
+
+    public short shortValue() {
+        return (short)value;
+    }
+
+    public String toString() {
+        return Integer.toString(value);
+    }
+
+    public static String toString(byte b) {
+        return Integer.toString(b);
+    }
+
+    public static Byte valueOf(byte b) {
+        return new Byte(b);
+    }
+
+    public static Byte valueOf(String s)
+        throws NumberFormatException {
+        return new Byte(Byte.parseByte(s, 10));
+    }
+
+    public static Byte valueOf(String s, int radix)
+        throws NumberFormatException {
+        return new Byte(Byte.parseByte(s, radix));
+    }
 }
diff --git a/classes/java/lang/Number.java b/classes/java/lang/Number.java
index f24abdc..4540fb9 100644
--- a/classes/java/lang/Number.java
+++ b/classes/java/lang/Number.java
@@ -1,10 +1,13 @@
 package java.lang;
 
-public class Number {
+public abstract class Number {
     public byte byteValue() {
         return (byte)intValue();
     }
 
+    public Number() {
+    }
+
     public abstract double doubleValue();
 
     public abstract float floatValue();