How to get an output from JUnit assertEquals() method and put it into a variable?

I have a JUnit test case here to test a simple class. Basically the class contains just one method called 'sum' that returns the sum of two numbers. To test if this is right I use the following method: Assert.assertEquals(2, my_object.sum(1, 2)); The result displays in a tab on eclipse, in a section called "Failure Trace". The message says: junit.framework.AssertionFailedError: expected:<2> but was:<3>. Is it possible to get this message and put it into a String variable?