Like every other unit test frameworks, JUnit helps to find out bugs in a Java code snippet or any other indivisible software component. JUnit ensures that every logical component of the system is working with optimal performance. Thus it focuses only on individual modules and doesn’t pay any attention to the connections between these entities.
JUnit is a regression testing technique for Java based software systems. A regression testing framework detects errors arising out as a result of code modification. This may be necessary for adding a new functional requirement or upgrading the system for the purpose of making a new stable release.
Without using JUnit the programmer will have to use the “println()” function to output faults on the console. With JUnit this is mostly automated. JUnit aggregates the results of the tests performed in a well structured manner. Without JUnit this might be almost impossible and may result into mess of test data, decreasing productivity and increasing costs.
With JUnit the programmer has the advantage to repeat the test designs. This helps in quick generation of tests and thus the process of writing code, in a test driven development.