Executing an expression evaluates an expression but does not display a result.
If you select the expression to execute and click the Execute button in the toolbar, no result is displayed, but the code is executed.
For example, if you type and highlight
System.out.println("Hello World"), and click the Execute button, Hello World
appears in the Console view, but no result is displayed in the scrapbook editor or the Expressions view.
Displaying the result of evaluating an expression
Inspecting the result of evaluating an expression
Viewing runtime exceptions