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A method should never Methods must not throw RuntimeException, Exception, or Exception. This is because handling these Throwable. Handling these exceptions requires catching RuntimeException, which is forbidden in EXC32disallowed by ERR08-J. Do not catch NullPointerException or any of its ancestors. Moreover, throwing a RuntimeException. can lead to subtle errors; for example, a caller cannot examine the exception to determine why it was thrown and consequently cannot attempt recovery.

Methods can throw a specific Instead, always throw an exception subclassed from Exception or RuntimeException. It Note that it is permissible to construct an exception class specifically for a single throw statement.

Noncompliant Code Example

The following function takes isCapitalized() method in this noncompliant code example accepts a string and returns true if it when the string consists of a capital letter succeeded followed by lowercase letters. To handle corner cases, it checks for them and throws exceptions if they would prevent normal analysisThe method also throws a RuntimeException when passed a null string argument.

boolean isCapitalized(String s) {
  if (s == null) {
    throw new RuntimeException("Null String");
  }
  if (s.equals("")) {
    return true;
  }
  String first = s.substring( 0, 1);
  String rest = s.substring( 1);
  return (first.equals( first.toUpperCase()) &&
          rest.equals( rest.toLowerCase()));
}

In order to handle the case of passing in a null string, code calling this function would have to catch RuntimeException, which violates EXC32A calling method must also violate ERR08-J. Do not catch NullPointerException or any of its ancestors to determine whether the RuntimeException was thrown.

Compliant Solution

An exception specifically devoted to the error would be more appropriate.This compliant solution throws NullPointerException to denote the specific exceptional condition:

boolean isCapitalized(String s) {
  if (s == null) {
    throw new NullPointerException();
  }
  if (s.equals("")) {
    return true;
  }
  String first = s.substring( 0, 1);
  String rest = s.substring( 1);
  return (first.equals( first.toUpperCase()) &&
          rest.equals( rest.toLowerCase()));
}

Note that the null check is redundant; if it were removed, the subsequent call to s.equals("") would throw a NullPointerException when s is null. However, the null check explicitly indicates the programmer's intent. More complex code may require explicit testing of invariants and appropriate throw statements.

Noncompliant Code Example

This noncompliant code example specifies the Exception class in the throws clause of the method declaration for the doSomething() method:

private void doSomething() throws Exception {
  //...
}

Compliant Solution

This compliant solution declares a more specific exception class in the throws clause of the method declaration for the doSomething() method:

private void doSomething() throws IOException {
  //...
}

Exceptions

ERR07-J-EX0: Classes that sanitize exceptions to comply with a security policy are permitted to translate specific exceptions into more general exceptions. This translation could potentially result in throwing RuntimeException, Exception, or Throwable in some cases, depending on the requirements of the security policy.

Risk Assessment

Throwing RuntimeException, Exception, or General Throwable prevents classes from catching your exception the intended exceptions without catching other unintended exceptions as well.

Automated Detection

...

TODO

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this rule on the CERT website.

References

\[[MITRE 09|AA. Java References#MITRE 09]\] [CWE ID 397|http://cwe.mitre.org/data/definitions/397.html] "Declaration of Throws for Generic Exception", [CWE ID 537|http://cwe.mitre.org/data/definitions/537.html] "Information Leak Through Java Runtime Error Message"
\[[Goetz 04b|AA. Java References#Goetz 04b]\]

Tool	Version	Checker	Description
CodeSonar	Include Page CodeSonar_V CodeSonar_V	JAVA.STRUCT.EXCP.BROAD	Broad Throws Clause (Java)
Parasoft Jtest	Include Page Parasoft_V Parasoft_V	CERT.ERR07.NTX CERT.ERR07.NTERR	Avoid declaring methods to throw general or unchecked Exception types Do not throw exception types which are too general or are unchecked exceptions
SonarQube	Include Page SonarQube_V SonarQube_V	S112	Generic exceptions should never be thrown

Related Guidelines

Bibliography

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Image Added Image Added Image AddedEXC03-J. Try to recover gracefully from system errors      10. Exceptional Behavior (EXC)      EXC30-J. Do not exit abruptly from a finally block