Java – Byte array is not working in JAXB classes

javajaxb

I am trying to use byte array like this (JAXB class). However, I am getting all 0s in the msg field even though I pass valid characters. The "id" and "myid" fields are parsed successfully and it is failing for the byte array field.

@XmlRootElement(name = "testMessage")
@XmlAccessorType(XmlAccessType.FIELD)
public class TestMessage
{
    @XmlAttribute
    private Integer id;

    @XmlElement(name = "myid")
    private Long myid;

    @XmlElement(name = "msg")
    private byte[] msg;
}

Best Answer

Using JAXB of Java 1.6.0_23 i get the following xml file for a TestMessage instance:

TestMessage testMessage = new TestMessage();
testMessage.id = 1;
testMessage.myid = 2l;
testMessage.msg = "Test12345678".getBytes();

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<testMessage id="1">
    <myid>2</myid>
    <msg>VGVzdDEyMzQ1Njc4</msg>
</testMessage>

If you unmarshall this xml content you should get back the TestMessage instance including the msg byte array (which is base64 encoded in the xml file).

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Java – How to test a class that has private methods, fields or inner classes

Update:

Some 10 years later perhaps the best way to test a private method, or any inaccessible member, is via @Jailbreak from the Manifold framework.
@Jailbreak Foo foo = new Foo();
// Direct, *type-safe* access to *all* foo's members
foo.privateMethod(x, y, z);
foo.privateField = value;
This way your code remains type-safe and readable. No design compromises, no overexposing methods and fields for the sake of tests.

If you have somewhat of a legacy Java application, and you're not allowed to change the visibility of your methods, the best way to test private methods is to use reflection.

Internally we're using helpers to get/set private and private static variables as well as invoke private and private static methods. The following patterns will let you do pretty much anything related to the private methods and fields. Of course, you can't change private static final variables through reflection.

Method method = TargetClass.getDeclaredMethod(methodName, argClasses);
method.setAccessible(true);
return method.invoke(targetObject, argObjects);

And for fields:

Field field = TargetClass.getDeclaredField(fieldName);
field.setAccessible(true);
field.set(object, value);

Notes:
1. TargetClass.getDeclaredMethod(methodName, argClasses) lets you look into private methods. The same thing applies for getDeclaredField.
2. The setAccessible(true) is required to play around with privates.

Java – Create ArrayList from array

new ArrayList<>(Arrays.asList(array));

Best Answer

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