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Eclipse 3.3 - and I guess also other Java IDEs - provides a Code Formatter option according the Java Convention by Sun. You may import the Eclipse Code Formatter Profile Java Conventions without tabs, which differs from Eclipse's build-in Java Convention Formatter Profile only by the Indentation Tab policy modified from Mixed to Spaces only.
In order to do it within Eclipse 3.3, import the code formatting settings from this wiki. Download download the Eclipse settings (java-conventions-without-tabs.xml) which are attached to the Coding Standards page. In Eclipse, click on Windows, Preferences, and then navigate to the Java/Code Style/Formatter section. Click on Import, and select the java-conventions-without-tabs.xml file. Click on OK to make these your active formatting settings.
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