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Add Comments and Javadocs in Eclipse With a Single Keystroke

· Java Zone

What every Java engineer should know about microservices: Reactive Microservices Architecture.  Brought to you in partnership with Lightbend.

When you want to work with comments in Eclipse, you could use the slow way of moving to the start of the line, pressing // and then repeating this for all the lines you have.

Or you could use the quick way of adding a comment with a single keystroke no matter where the cursor’s positioned in the statement.

The same goes for Javadocs – there are just too many things to type before you can start commenting the good stuff. That’s why Eclipse also has a shortcut that let’s you add Javadoc to a field, method or class.

Keyboard shortcuts for comments and JavaDocs

Here are the keyboard shortcuts for manipulating comments.

Command Description
Ctrl+/ Toggle Comment Add/remove line comments (//…) from the current line. The position of the cursor can be anywhere on the line. Works with multiple selected lines as well.
Ctrl+Shift+/ Add Block Comment Wrap the selected lines in a block comment (/*… */).
Ctrl+Shift+\ Remove Block Comment Remove a block comment (/*… */) surrounding the selected lines.
Alt+Shift+J Add Javadoc Comment Add a Javadoc comment to the active field/method/class. See the notes below for more details on where to position the cursor.

Bear the following in mind when using Add Javadoc comment (Alt+Shift+J):

  • To add a comment to a field, position the cursor on the field declaration.
  • To add a comment to a method, position the cursor anywhere in the method or on its declaration.
  • To add a comment to a class, the easiest is to position the cursor on the class declaration. Also works if you’re in the class, but not in a method, field or nested type.
  • The Javadoc comment inserted is based on the Code Templates defined  under Window > Preferences > Java > Code Style > Code Templates. If you expand the Comments section, you can change the default for Fields, Methods, Types (eg. classes), etc.

Here’s a video to give you an idea of how fast and easy it is to add/remove comments using these shortcuts. The video shows toggling of single line comments, block comments and also adding a Javadoc comment to the method and class.

Once I’ve commented out lines, I often find myself copying them and moving them around (eg. to try different variations of the code). You can do this faster by moving and copying lines using with a single keystroke.

You can also have Eclipse format the comments whenever you save, saving you formatting time.


From http://eclipseone.wordpress.com/2010/05/05/add-comments-and-javadocs-in-eclipse-with-a-single-keystroke/

Microservices for Java, explained. Revitalize your legacy systems (and your career) with Reactive Microservices Architecture, a free O'Reilly book. Brought to you in partnership with Lightbend.


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