DrJava is a simple and light IDE for Java development. It is a free, open source IDE primarily designed for students. But it also includes powerful features for more advanced users. It has integrated debuggers, support unit testing with Junit and tools to generate javadocs. DrJava is available for multiple platforms, including Windows, Linux, and Macintosh.
DrJava is an ongoing project at Rice University, Texas, developed and maintain by students. DrJava shares the goal of providing a preparatory training environment that decreases the fear factor experienced by beginning students. This project provides an interface that is simple, interactive, and with a focus on the language.
REPL – Read Eval Print Loop
The eminent feature of DrJava is the ‘interactions pane,’ a ‘read-eval-print loop’ (REPL) for evaluating Java expressions and statements interactively. Functional languages such as ‘Scheme’ have long used Read Eval Print Loop. That make easy program development. Users experiment with Java constructs by typing an expression or statement will compile immediately without having a complete java code. REPL makes it possible to completely avoid the difficulties of Java I/O at the introductory level by using parameters and function return values. The interface is text based, and does require using Java syntax. This design was deliberately chosen so that only a single medium is required for dealing with program development, in contrast to the combination of UML and Java source code. Interactions can easily process graphic objects.
DrJava keep up a focus on Java and it gives two components, a definitions pane and an interactions pane in a ‘single window environment’. In definitions pane, when a class is compiled, it is directly available in the interactions pane for another uses. The Read Eval Print Loop features of the interactions pane boost understandable functional programming in association with the object-oriented model. The interactions pane keeps a history for comfortably recollecting the already inserted commands. This decreases the typing needed when going for experiential evaluations.
A Lift Current Interaction to Definitionscommand copies an interaction into the editor. This gives a comfortable way to move experiential tests into a JUnit test to make them repeatable. Since each class method can be executed independently, the interactions pane is an impressive tool for small testing and troubleshooting. It also contains a debugger that helps adding breakpoints and explaining watches. In debug mode when execution is break up at a breakpoint, the interactions pane can be used to check or modify state variables using Java statements and expressions. Again the design approach was to maintain an easy and steady interface throughout. It’s compiler shows all syntax errors by parsing the file. Clicking an error message highlights the error in the source code.
Dr.Java’s editor supplies automatic braces /parenthesis matching, comment /quotation highlighting and indentation that is refreshed in every keypress. A complete Java class can properly formated by an ‘Indent lines’ command. The editor supports several documents but does not arrange files into projects. To organize files, it is necessary to use the operating system’s file management facilities. Another features of DrJava contain built-in support for JUnit test cases creation of javadoc and it’s preview.
DrJava’s developers suggest that the IDE is useful beyond the beginner level, and cite advanced courses at Rice University that feature projects for extending the tool. One such project produced a DrJava plugin available for the Eclipse IDE that should ease the transition to the more powerful features of a professional IDE.
IDE’s are very important tools for easing the entry of students into software development courses. Dr.Java serve easy interfaces especially designed for teaching. It encourage cumulative development and associative experimentation, which will possibly the most important feature of this IDE. DrJava provide excellent options for simple entry level software development in Java. DrJava has a cleaner and easier interface that manages a focus on the Java language.