add a bunch of classes to classpath and flesh out a few existing ones

classpath/java/lang/Byte.java

@@ -1,6 +1,6 @@
 package java.lang;
 
-public final class Byte {
+public final class Byte extends Number {
   private final byte value;
 
   public Byte(byte value) {
@@ -10,4 +10,24 @@ public final class Byte {
   public byte byteValue() {
     return value;
   }
+
+  public short shortValue() {
+    return value;
+  }
+
+  public int intValue() {
+    return value;
+  }
+
+  public long longValue() {
+    return value;
+  }
+
+  public float floatValue() {
+    return (float) value;
+  }
+
+  public double doubleValue() {
+    return (double) value;
+  }
 }