jGRASP

The use of an integrated development environment (IDE) can help a programmer work through the steps of developing a program. An IDE brings together (integrates) several different tools used in the program development process. For example, the jGRASP IDE includes a editor for entering and modifying Java programs, runs the compiler to translate the Java program to byte code, and runs the program on the CPU via the Java Virtual Machine. The jGRASP IDE also has a debugger. A debugger allows the programmer to examine a program as it runs -- the programmer can watch the flow instructions as they are processed by the CPU, and look at the contents of the variables as the program runs.

The jGRASP IDE can be downloaded for free from http://www.jgrasp.org. The jGRASP website also has a very good tutorial on jGRASP which you should read. Below is a quick example that shows how to edit, compile, and run a Java program with jGRASP. The example creates a Demo Java class.

Double click on the jGRASP icon to start jGRASP:

Click File, click New, and then click Java to open an empty text window in the jGRASP editor.

Now use the jGRASP editor to "type in" your program, then save it to the disk drive as Demo.java (for this demonstration it is a better idea to copy the text from this page and paste it into jGRASP). Follow the instructions shown on the images, below:

Compile the Java program (translate it to byte code). This will create the file Demo.class.

Run the program. The byte code that you created here, along with some Java library code, will get loaded into memory and run through the Java Virtual Machine (JVM). In this particular case, the output generated by the program simply goes to the Run I/O output console (jGRASP's bottom window):