Auto‑Generate Class and Method Javadoc Templates in IntelliJ IDEA

Class Comment Template

Open Settings → Editor → File and Code Templates, select the Class tab and replace the default content with a custom template that inserts author and date information. The template uses IDEA’s built‑in variables such as ${YEAR}, ${MONTH}, ${DAY} and ${TIME}:

/**
 * @author jitwxs
 * @date ${YEAR}年${MONTH}月${DAY}日 ${TIME}
 */

After saving, any newly created Java class will automatically contain this header.

Method Comment Template

Method comments are more complex, so we create a Live Template:

Open Settings → Editor → Live Templates.

Click the + button, choose 2. Template Group..., name the group (e.g., userDefine).

Select the new group, click + again, and choose 1. Live Template.

Set Abbreviation to * (the trigger key) and ensure Expand with is set to Enter.

In the Template text field paste the following (note the first line starts directly with * and there is no leading / slash):

*
 * @author jitwxs
 * @date $date$ $time$ $param$ $return$
 */

Set the Applicable Contexts to Java so the template works for all Java files.

Next, define the variables used in the template: date and time use IDEA’s built‑in functions (select them from the dropdown). param and return require custom Groovy scripts because the default implementations either always generate a line or produce an unwanted void entry.

Groovy script for param (generates @param lines only when parameters exist):

groovyScript("def result = ''; def params = \"${_1}\".replaceAll('[\\[|\\]|\\s]', '').split(',').toList(); for(i = 0; i < params.size(); i++) { if(params[i] != '') result += '* @param ' + params[i] + (i < params.size() - 1 ? '
 ' : ''); }; return result == '' ? null : '
 ' + result", methodParameters())

Groovy script for return (adds @return only when the method does not return void):

groovyScript("return \"${_1}\" == 'void' ? null : '
 * @return ' + \"${_1}\"", methodReturnType())

Make sure the Skip if defined option is unchecked, otherwise the cursor would jump over already defined sections.

Verification

When you create a new class, the class header appears automatically. When you invoke the method template (type * and press Enter) inside a Java file, the generated Javadoc adapts to the method signature, handling cases such as no parameters, single or multiple parameters, no return value, and a return value.

Q & A

Why must the abbreviation be * and Expand with be Enter ? The template is triggered by the combination * + Enter, which IDEA interprets as the start of a Javadoc comment ( /**).

Why is there an empty * line in the template? It reserves a place for a method description; you can delete it if not needed.

Why are $time$ and $param$ placed together? The custom param script expects the placeholder to be on the same line to handle backspace correctly.

Why implement return manually instead of using methodReturnType() ? The default returns void for methods without a return value, which is unnecessary; the custom script only emits @return when a real return type exists.

Why isn’t $return$ on a separate line? When methodReturnType() returns null, placing it on a separate line would cause backspace handling issues, so it is kept inline.

After saving the settings, the templates work as described.