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According to the Java Language Specification, §11.1.1, "The Kinds of Exceptions" [JLS 2013],

The unchecked exceptions classes are the class RuntimeException and its subclasses, and the class Error and its subclasses. All other exception classes are checked exception classes.

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Catching Throwable is disallowed in general by ERR08-J. Do not catch NullPointerException or any of its ancestors, but it is permitted when filtering exception traces by the exception ERR08-EX0 in that rule.

Noncompliant Code Example

This noncompliant code example generates a StackOverflowError as a result of infinite recursion. It exhausts the available stack space and may result in denial of service.

public class StackOverflow {
  public static void main(String[] args) {
    infiniteRun();
    // ...
  }
    
  private static void infiniteRun() {
    infiniteRun();
  }
}

Compliant Solution

This compliant solution shows a try-catch block that can be used to capture java.lang.Error or java.lang.Throwable. A log entry can be made at this point, followed by attempts to free key system resources in the finally block.

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Note that this solution catches Throwable in an attempt to handle the error; it falls under exception ERR08-EX2 in ERR08-J. Do not catch NullPointerException or any of its ancestors.

Applicability

Allowing a system error to abruptly terminate a Java program may result in a denial-of-service vulnerability.

Bibliography

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