The Java development toolkit (JDT) contributes a scrapbook facility that can be used to experiment and evaluate Java code snippets before building a complete Java program. Snippets are edited and evaluated in the Scrapbook page editor, with resultant problems reported in the editor.
From a Java scrapbook editor, you can select a code snippet, evaluate it, and display the result as a string. You can also show the object that results from evaluating a code snippet in the debuggers' Expressions View.
Java development tools (JDT)
Creating a Java scrapbook page
Displaying the result of evaluating an expression
Inspecting the result of evaluating an expression
New Java Scrapbook Page wizard
Java Scrapbook page