Add Java verifier

[dinoboff]

Compile solution and test in memory and run the test case:

• the solution should implement a class name "SingPath"
• the solution needs to implement the body of a TestCase method and its local includes: "static org.junit.Assert.", "junit.framework.", "import com.singpath.SolutionRunner";

Note that the verifier only support JSON POST requests.

[dinoboff]

@SingaporeClouds

Unlike the Beanshell solution I cannot show a table of all tests calls; I can only show the failed calls.

I also do not know how to capture the standard streams when using org.junit.runner.JUnitCore.runClasses. I am assuming multiple threads (like multiple verification request thread) are using the same System.out and I cannot set my own printer to capture it.

If it's an issue, I could compile the solution memory using the jdk and run the tests with Beanshell. The tests would have to be tweaked to work in Beanshell compare to normal Java code. For example, the test code would have to not use varargs: Arrays.asList("a","b","c") should be written in the tests as Arrays.asList([]String{"a","b","c"}).