Saturday, October 6, 2018

StackOverFlowError: Causes & Solutions

StackOverFlowError is one of the common confronted JVM error. In this blog post lets learn inner mechanics of thread stacks, reasons that can trigger StackOverFlowError and potential solutions to address this error.

To gain deeper understanding in to StackOverFlowError, let's review this simple program:

public class SimpleExample {

      public static void main(String args[]) {

      public static void a() {

            int x = 0;

      public static void b() {

            Car y = new Car();           

      public static void c() {

            float z = 0f;

This program is very simple with following execution code:

1.       main() method is invoked first
2.       main() method invokes a() method. Inside a() method integer variable ‘x’ is initialized to value 0.
3.       a() method in turn invokes b() method. Inside b() method Car object is constructed and assigned to variable ‘y’.
4.       b() method in turn invokes c() method. Inside c() method float variable ‘z’ is initialized to value 0.

Now let’s review what happens behind the scenes when above simple program is executed. Each thread in the application has its own stack. Each stack has multiple stack frames. Thread adds the methods it’s executing, primitive data types, object pointers, return values to its stack frame in the sequence order in which they are executed.

Fig 1: Thread's Stack frame.

Java - Cucumber Hello World example

In the previous article we have seen JBehave Hello World example. In this article we will see same Hello World example but with using Cucumber.

Like JBehave, Cucumber is also used for behavior-driven development (BDD) testing. To know more about Cucumber click here.

Below is the eclipse folder structure -