Class UncommentedMainCheck

All Implemented Interfaces:
Configurable, Contextualizable

public class UncommentedMainCheck extends AbstractCheck

Detects uncommented main methods.

Rationale: A main method is often used for debugging purposes. When debugging is finished, developers often forget to remove the method, which changes the API and increases the size of the resulting class or JAR file. With the exception of the real program entry points, all main methods should be removed or commented out of the sources.

  • Property excludedClasses - Specify pattern for qualified names of classes which are allowed to have a main method. Type is java.util.regex.Pattern. Default value is "^$".

To configure the check:

 <module name="UncommentedMain"/>
 

Example:

 public class Game {
    public static void main(String... args){}   // violation
 }

 public class Main {
    public static void main(String[] args){}   // violation
 }

 public class Launch {
    //public static void main(String[] args){} // OK
 }

 public class Start {
    public void main(){}                       // OK
 }

 public record MyRecord1 {
    public void main(){}                       // violation
 }

 public record MyRecord2 {
    //public void main(){}                       // OK
 }

 

To configure the check to allow the main method for all classes with "Main" name:

 <module name="UncommentedMain">
   <property name="excludedClasses" value="\.Main$"/>
 </module>
 

Example:

 public class Game {
    public static void main(String... args){}   // violation
 }

 public class Main {
    public static void main(String[] args){}   // OK
 }

 public class Launch {
    //public static void main(String[] args){} // OK
 }

 public class Start {
    public void main(){}                       // OK
 }

 public record MyRecord1 {
    public void main(){}                       // OK
 }

 

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

  • uncommented.main
Since:
3.2
  • Field Details

    • MSG_KEY

      public static final String MSG_KEY
      A key is pointing to the warning message text in "messages.properties" file.
      See Also:
  • Constructor Details

    • UncommentedMainCheck

      public UncommentedMainCheck()
  • Method Details

    • setExcludedClasses

      public void setExcludedClasses(Pattern excludedClasses)
      Setter to specify pattern for qualified names of classes which are allowed to have a main method.
      Parameters:
      excludedClasses - a pattern
    • getAcceptableTokens

      public int[] getAcceptableTokens()
      Description copied from class: AbstractCheck
      The configurable token set. Used to protect Checks against malicious users who specify an unacceptable token set in the configuration file. The default implementation returns the check's default tokens.
      Specified by:
      getAcceptableTokens in class AbstractCheck
      Returns:
      the token set this check is designed for.
      See Also:
    • getDefaultTokens

      public int[] getDefaultTokens()
      Description copied from class: AbstractCheck
      Returns the default token a check is interested in. Only used if the configuration for a check does not define the tokens.
      Specified by:
      getDefaultTokens in class AbstractCheck
      Returns:
      the default tokens
      See Also:
    • getRequiredTokens

      public int[] getRequiredTokens()
      Description copied from class: AbstractCheck
      The tokens that this check must be registered for.
      Specified by:
      getRequiredTokens in class AbstractCheck
      Returns:
      the token set this must be registered for.
      See Also:
    • beginTree

      public void beginTree(DetailAST rootAST)
      Description copied from class: AbstractCheck
      Called before the starting to process a tree. Ideal place to initialize information that is to be collected whilst processing a tree.
      Overrides:
      beginTree in class AbstractCheck
      Parameters:
      rootAST - the root of the tree
    • leaveToken

      public void leaveToken(DetailAST ast)
      Description copied from class: AbstractCheck
      Called after all the child nodes have been process.
      Overrides:
      leaveToken in class AbstractCheck
      Parameters:
      ast - the token leaving
    • visitToken

      public void visitToken(DetailAST ast)
      Description copied from class: AbstractCheck
      Called to process a token.
      Overrides:
      visitToken in class AbstractCheck
      Parameters:
      ast - the token to process