Name: apR10229 Date: 01/29/2003



ObjectStreamField.getType() returns Object.class for non-primitive types
(i.e. java.lang.String). This bug is closely similar to a bug 4427881,
that was fixed and integrated in merlin-beta.

API Doc says:
>public Class getType()
>
> Get the type of the field.
>
> Returns:
> the Class object of the serializable field

ObjectStreamField.getType() returns Object.class
for non-primitive types of fields instead of correct class object,
representing a given type, as pointed in the API Documentation.

There is an example below for reproducing this bug.
(Example.java and CSer.java)

--------------- example output ------------------------

<pav@libra(pts/8).262> javac Example.java CSer.java
<pav@libra(pts/8).263> java -classpath . Example
Results for ObjectStreamField of type String:
Returned typeString: Ljava/lang/String;
Returned type: class java.lang.Object
Expected type: class java.lang.String
<pav@libra(pts/8).264>


------------- end of output ---------------------------

-------------------- Example.java ---------------------

import java.io.*;
import java.util.*;

public class Example {

    public Example() {
        // Serialize object to a byte stream
        ByteArrayOutputStream arrOutStream = new ByteArrayOutputStream();
        CSer serObj = new CSer("TestString");
        try {
            ObjectOutputStream os = new ObjectOutputStream(arrOutStream);
            os.writeObject(serObj);
            os.flush();
            os.close();
        } catch(IOException e) {
            System.out.println("Serialization has broken."+
            " Unexpected exception: "+e);
            e.printStackTrace();
        }

        // Deserialize object
        ByteArrayInputStream arrInStream = new
            ByteArrayInputStream(arrOutStream.toByteArray());
        CSer o = null;
        try {
            ObjectInputStream is = new ObjectInputStream(arrInStream);
            o = (CSer) is.readObject();
            is.close();
        } catch(IOException e) {
            System.out.println("Deserialization has broken. "+
            "Unexpected exception: "+e);
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            System.out.println("Deserialization has broken. "+
            "Unexpected exception: "+e);
            e.printStackTrace();
        }

        // Obtain ObjectStreamClass of deserialized object
        ObjectStreamClass osc = o.getObjectStreamClass();
        testField(osc.getField("strFieldShared"));
    }

    public void testField(ObjectStreamField osf) {
        System.out.println("Results for ObjectStreamField of "+
        "type String:");
        System.out.println("Returned typeString: "+osf.getTypeString());
        System.out.println("Returned type: "+osf.getType());
        System.out.println("Expected type: class java.lang.String");
    }

    public static void main(String[] args) {
        Example e = new Example();
    }

}

------------------- end of Example.java ---------------

----------------- CSer.java ---------------------------

import java.io.*;

class CSer implements Serializable {
    String strFieldShared;
    ObjectInputStream.GetField readFields = null;

    public CSer(String s) {
        strFieldShared = s;
    }

    private static final ObjectStreamField[] serialPersistentFields = {
        new ObjectStreamField("strFieldShared", String.class, false),
    };

    private void readObject(ObjectInputStream s)
                throws IOException, ClassNotFoundException {
        readFields = s.readFields();
        strFieldShared = (String) readFields.get("strFieldShared",
        "No such field");
    }

    private void writeObject(ObjectOutputStream s)
                throws IOException {
        ObjectOutputStream.PutField wroteFields = s.putFields();
        wroteFields.put("strFieldShared", strFieldShared);
        s.writeFields();
    }

    public ObjectStreamClass getObjectStreamClass() {
        return readFields.getObjectStreamClass();
    }
}

---------------- end of CSer.java ---------------------

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