Package com.puppycrawl.tools.checkstyle.checks.coding

Class IllegalCatchCheck

  • All Implemented Interfaces:
    Configurable, Contextualizable
    public final class IllegalCatchCheck
extends AbstractCheck

    Checks that certain exception types do not appear in a catch statement.

    Rationale: catching java.lang.Exception, java.lang.Error or java.lang.RuntimeException is almost never acceptable. Novice developers often simply catch Exception in an attempt to handle multiple exception classes. This unfortunately leads to code that inadvertently catches NullPointerException, OutOfMemoryError, etc.

    • Property illegalClassNames - Specify exception class names to reject. Type is java.lang.String[]. Default value is Error, Exception, RuntimeException, Throwable, java.lang.Error, java.lang.Exception, java.lang.RuntimeException, java.lang.Throwable.

    To configure the check: 

     <module name="IllegalCatch"/>

    Example:

     try {
     // some code here
 } catch (Exception e) { // violation

 }

 try {
     // some code here
 } catch (ArithmeticException e) { // OK

 } catch (Exception e) { // violation, catching Exception is illegal
                           and order of catch blocks doesn't matter
 }

 try {
     // some code here
 } catch (ArithmeticException | Exception e) { // violation, catching Exception is illegal

 }

 try {
     // some code here
 } catch (ArithmeticException e) { // OK

 }

    To configure the check to override the default list with ArithmeticException and OutOfMemoryError: 

     <module name="IllegalCatch">
   <property name="illegalClassNames" value="ArithmeticException,
               OutOfMemoryError"/>
 </module>

    Example:

     try {
     // some code here
 } catch (OutOfMemoryError e) { // violation

 }

 try {
     // some code here
 } catch (ArithmeticException e) { // violation

 }

 try {
     // some code here
 } catch (NullPointerException e) { // OK

 } catch (OutOfMemoryError e) { // violation

 }

 try {
     // some code here
 } catch (ArithmeticException | Exception e) {  // violation

 }

 try {
     // some code here
 } catch (Exception e) { // OK

 }

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • illegal.catch
    Since:
    3.2

    • Field Detail

      • MSG_KEY

        public static final java.lang.String MSG_KEY
        A key is pointing to the warning message text in "messages.properties" file.
        See Also:
        Constant Field Values

    • Constructor Detail

      • IllegalCatchCheck

        public IllegalCatchCheck()

    • Method Detail

      • setIllegalClassNames

        public void setIllegalClassNames​(java.lang.String... classNames)
        Setter to specify exception class names to reject.
        Parameters:
        classNames - array of illegal exception classes

      • 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:
        TokenTypes

      • 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:
        TokenTypes

      • 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:
        TokenTypes

      • visitToken

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