Fix serialization issue. currentPos was not correctly serialized and consequently startxref was wrong for copied documents

Author: Snipx

io/src/main/java/com/itextpdf/io/source/OutputStream.java

@@ -46,7 +46,11 @@ This file is part of the iText (R) project.
 
 import com.itextpdf.io.IOException;
 
-public class OutputStream<T extends java.io.OutputStream> extends java.io.OutputStream {
+import java.io.Serializable;
+
+public class OutputStream<T extends java.io.OutputStream> extends java.io.OutputStream implements Serializable {
+
+    private static final long serialVersionUID = -5337390096148526418L;
 
     //long=19 + max frac=6 => 26 => round to 32.
     private final ByteBuffer numBuffer = new ByteBuffer(32);
@@ -233,4 +237,22 @@ public void reset() {
         } else
             throw new IOException(IOException.BytesCanBeResetInByteArrayOutputStreamOnly);
     }
+
+    /**
+     * This method is invoked while deserialization
+     */
+    private void readObject(java.io.ObjectInputStream in) throws java.io.IOException, ClassNotFoundException {
+        in.defaultReadObject();
+    }
+
+    /**
+     * This method is invoked while serialization
+     */
+    private void writeObject(java.io.ObjectOutputStream out) throws java.io.IOException {
+        java.io.OutputStream tempOutputStream = outputStream;
+        outputStream = null;
+        out.defaultWriteObject();
+        outputStream = tempOutputStream;
+    }
+
 }

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfOutputStream.java

@@ -52,15 +52,15 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.PdfException;
 import com.itextpdf.kernel.crypto.OutputStreamEncryption;
 import com.itextpdf.kernel.pdf.filters.FlateDecodeFilter;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
-import java.io.Serializable;
 import java.text.MessageFormat;
 import java.util.Map;
 
-public class PdfOutputStream extends OutputStream<PdfOutputStream> implements Serializable{
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class PdfOutputStream extends OutputStream<PdfOutputStream> {
 
     private static final long serialVersionUID = -548180479472231600L;