Configuring the Eclipse IDE

Why change the Eclipse configuration?

By the default Eclipse IDE is configured in a way to make the majority of developers happy. However that may not fit your needs or your taste. By changing some the IDE settings you may be able to use Eclipse more efficiently and produce better code.

Please note : All settings on this page are recommendations and show my personal preferences. If something does not work for you or you disagree with it please feel free to ignore the corresponding chapters. After all your settings are as right and wrong as mine are.

Settings for Text Editors

The following settings apply to all text editors include Java and XML editors. To change these settings open the IDE preferences and go to General > Editors > Text Editors:

• Insert spaces for tabs will replace tabs with spaces and avoid mix of tabs and spaces which can result in misalignment in some systems. The number of spaces for each tab is specified in Displayed tab width. Keep in mind for Java Editors there is a separate setting for this.
• Show line numbers will display the line number on the left side of the text editor. This helps when searching for bugs based on exception stacktraces or when talking with colleagues about the code.
• Show whitespace characters similar to Word this will show spaces, tabs and returns. This is sometimes useful when lines are much indented or non-ASCII characters. The link configure visibility lets you choose which characters to show and also the transparency level.

Typing in Java

The following settings can be found in the preferences in Java > Editor > Typing.

• An often occurring problem is as missing semicolon or brace in a code line. Enabling the Automatically insert at correct position option will add the semicolon or brace at the right place in the line independent where you type.
• Escape text when pasting into a string literal will automatically escape all special characters when a text (e.g. HTML or XML) is pasted into a string (e.g. String a = "" => paste between ").

Highlighting of brackets

It is useful to see where the current code block starts and ends. In the Eclipse preference under Java > Editor you can change the Bracket highlighting to Eclosing brackets. Now the enclosing () or {} will be highlighted when placing the cursor.

Link the editors with the Package Explorer view

Sometimes it is hard to find out where the file you have opened in an editor is physically located (e.g. which project, which package, which folder). Linking editors and Package Explorer make sure that the file from the current active editor is always selected in the Package Explorer. To enable or disable this feature click the link button in the Package Explorer:

Save Actions

Eclipse IDE has the option to cleanup your Java code when saving a file. The settings can be found in the preferences on the page Java > Editor > Save Actions.

• Tick Perform the selected actions on save to enable this feature.
• Format source code will apply the configured code formatting to the current file. Format all lines may take longer but will fix the entire file.
• Organize Imports will remove all unused imports from the file and minimize the number of warnings
• Additional actions can be defined using the Configure button on the right. There are some reasonable defaults already set the following can be added:
  • Remove unnecessary casts
  • Remove trailing white spaces on all lines
  • Correct indentation

Type filter

When using SWT or JFace controls it often happens that Eclipse can not automatically fix the imports since it does not know if java.awt.Button or org.eclipse.swt.widgets.Button is the right import. If you are not working with AWT or SWING in the workspace it is a good idea to filter their classes out, so that only SWT imports are left. This can be configured in the preferences on the page Java > Appearance > Type Filters:

• Add will allow to add a filter using wildcards (e.g. *,?). The Browse button in the add dialog can help finding the right packages.
• Remove will remove the selected filter from the configuration.

Autocompletion configuration

When writing a method in Java autocompletion can be used to complete the method. But sometimes the start is not right and instead of x.something you write x.anything. When you go back to the dot and trigger the autocompletion (CTRL+Space in Windows) you can now select the right method but will end up with x.somethinganything or x.something()anything because Eclipse inserted the method rather than overwrite. When using autocompletion Java will by default add the names of the method arguments as placeholders to be replaced with the right variables. However it is also possible to let Eclipse guess the best option and autofill the arguments with the corresponding variables. If that happens often you want to change this behavior in preferences on page Java > Editor > Content Assist:

• Completion overwrites will fix the mentioned behavior.
• Insert best guessed arguments in Fill method arguments and show guessed arguments will configure Eclipse to try guessing the right variable based on the current context.

Please Note : The guessing of the parameters does not free you from careful checking that the arguments are correct. Even if Eclipse gets it right in 90+ % of all cases.

Hungarian notation and this.

If you prefer a certain prefix or suffix scheme for naming your variable you can configure this in the preferences on page Java > Code Style. You can also configure Eclipse to use the this. qualifier when generating code involving member variables:

• Conventions for variable names tables allows to customize prefix and suffix for variables
• Qualify all generated field accesses with this. will enable the usage of this. in auto-generated code.