Additional of several interfaces which can be used in serialization

classpath/java/io/Externalizable.java

@@ -0,0 +1,16 @@
+/* Copyright (c) 2010, Avian Contributors
+
+   Permission to use, copy, modify, and/or distribute this software
+   for any purpose with or without fee is hereby granted, provided
+   that the above copyright notice and this permission notice appear
+   in all copies.
+
+   There is NO WARRANTY for this software.  See license.txt for
+   details. */
+
+package java.io;
+
+public interface Externalizable { 
+  public void readExternal(ObjectInput in);
+  public void writeExternal(ObjectOutput out);
+}

classpath/java/io/ObjectInput.java

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+/* Copyright (c) 2010, Avian Contributors
+
+   Permission to use, copy, modify, and/or distribute this software
+   for any purpose with or without fee is hereby granted, provided
+   that the above copyright notice and this permission notice appear
+   in all copies.
+
+   There is NO WARRANTY for this software.  See license.txt for
+   details. */
+
+package java.io;
+
+public interface ObjectInput {
+  public int available();
+  public void close();
+  public void read();
+  public void read(byte[] b);
+  public void read(byte[] b, int off, int len);
+  public Object readObject();
+  public long skip(long n);
+}

classpath/java/io/ObjectOutput.java

@@ -0,0 +1,20 @@
+/* Copyright (c) 2010, Avian Contributors
+
+   Permission to use, copy, modify, and/or distribute this software
+   for any purpose with or without fee is hereby granted, provided
+   that the above copyright notice and this permission notice appear
+   in all copies.
+
+   There is NO WARRANTY for this software.  See license.txt for
+   details. */
+
+package java.io;
+
+public interface ObjectOutput {
+  public void close();
+  public void flush();
+  public void write(byte[] b);
+  public void write(byte[] b, int off, int len);
+  public void write(int b);
+  public void writeObject(Object obj);
+}