FULL PRODUCT VERSION :
java version "1.7.0-internal"
Java(TM) SE Runtime Environment (build 1.7.0-internal-sm162706_05_oct_2006_15_12-b00)
Java HotSpot(TM) Client VM (build 1.6.0-rc-b100, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP Professional Service Pack 2

A DESCRIPTION OF THE PROBLEM :
The bean with initialized property could not be encoded/decoded successfully.

    public class GridBagConstraintsBeanGood {
        private GridBagConstraints gbc;

        public GridBagConstraints getGridBagConstraints() {
            return this.gbc;
        }

        public void setGridBagConstraints( GridBagConstraints gbc ) {
            this.gbc = gbc;
        }
    }

    public class GridBagConstraintsBeanBad {
        private GridBagConstraints gbc = new GridBagConstraints();

        public GridBagConstraints getGridBagConstraints() {
            return this.gbc;
        }

        public void setGridBagConstraints( GridBagConstraints gbc ) {
            this.gbc = gbc;
        }
    }

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Create instances of beans.
2. Set new value of the property for each of them.
3. Encode and decode modified instances.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
<?xml version="1.0" encoding="UTF-8"?>
<java version="1.7.0-internal" class="java.beans.XMLDecoder">
 <object class="GridBagConstraintsBeanGood">
  <void property="gridBagConstraints">
   <object class="java.awt.GridBagConstraints">
    <int>1</int>
    <int>2</int>
    <int>3</int>
    <int>4</int>
    <double>0.1</double>
    <double>0.2</double>
    <int>11</int>
    <int>3</int>
    <object class="java.awt.Insets">
     <int>1</int>
     <int>2</int>
     <int>4</int>
     <int>3</int>
    </object>
    <int>-1</int>
    <int>-2</int>
   </object>
  </void>
 </object>
 <object class="GridBagConstraintsBeanBad">
  <void property="gridBagConstraints">
   <object class="java.awt.GridBagConstraints">
    <int>1</int>
    <int>2</int>
    <int>3</int>
    <int>4</int>
    <double>0.1</double>
    <double>0.2</double>
    <int>11</int>
    <int>3</int>
    <object class="java.awt.Insets">
     <int>1</int>
     <int>2</int>
     <int>4</int>
     <int>3</int>
    </object>
    <int>-1</int>
    <int>-2</int>
   </object>
  </void>
 </object>
</java>
ACTUAL -
<?xml version="1.0" encoding="UTF-8"?>
<java version="1.7.0-internal" class="java.beans.XMLDecoder">
 <object class="GridBagConstraintsBeanGood">
  <void property="gridBagConstraints">
   <object class="java.awt.GridBagConstraints">
    <int>1</int>
    <int>2</int>
    <int>3</int>
    <int>4</int>
    <double>0.1</double>
    <double>0.2</double>
    <int>11</int>
    <int>3</int>
    <object class="java.awt.Insets">
     <int>1</int>
     <int>2</int>
     <int>4</int>
     <int>3</int>
    </object>
    <int>-1</int>
    <int>-2</int>
   </object>
  </void>
 </object>
 <object class="GridBagConstraintsBeanBad"/>
</java>