Description

Whitespace is defined by implementation of java.lang.Character.isWhitespace(char)

Left angle bracket ("<"):

• should be preceded with whitespace only in generic methods definitions.
• should not be preceded with whitespace when it is preceded method name or constructor.
• should not be preceded with whitespace when following type name.
• should not be followed with whitespace in all cases.

Right angle bracket (">"):

• should not be preceded with whitespace in all cases.
• should be followed with whitespace in almost all cases, except diamond operators and when preceding a method name, constructor, or record header.

Examples

To configure the check:

<module name="Checker">
  <module name="TreeWalker">
    <module name="GenericWhitespace"/>
  </module>
</module>

Examples with correct spacing:

class Example1 {
  List<String> l;
  public <T> void foo() {}
  List a = new ArrayList<>();
  Map<Integer, String> m;
  HashSet<Integer> set;
  record License<T>() {}
}

Examples with incorrect spacing:

class Example2 {
  List <String> l; // violation ''<' is preceded with whitespace.'
  public<T> void foo() {} // violation ''<' is not preceded with whitespace.'
  List a = new ArrayList<> (); // violation ''>' is followed by whitespace.'
  Map<Integer, String>m; // violation ''>' is followed by an illegal character.'
  HashSet<Integer > set; // violation ''>' is preceded with whitespace.'
  record License<T> () {} // violation ''>' is followed by whitespace.'
}

Example of Usage

• Google Style
• Sun Style
• Checkstyle Style

Violation Messages

• ws.followed
• ws.illegalFollow
• ws.notPreceded
• ws.preceded

All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.

Fully Qualified Name

com.puppycrawl.tools.checkstyle.checks.whitespace.GenericWhitespaceCheck

Use this fully qualified class name in configuration when an exact class reference is required.

Parent Module

TreeWalker