ExceptionUtils (The Adobe AEM Quickstart and Web Application.)

java.lang.Object
- org.apache.commons.lang.exception.ExceptionUtils

```
public class ExceptionUtils
extends java.lang.Object
```
Provides utilities for manipulating and examining Throwable objects.

Since:

1.0

Constructor Summary

Constructors
Constructor and Description

ExceptionUtils()
Public constructor allows an instance of ExceptionUtils to be created, although that is not normally necessary.

Constructors
Constructor and Description
`ExceptionUtils()` Public constructor allows an instance of `ExceptionUtils` to be created, although that is not normally necessary.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static void`	`addCauseMethodName(java.lang.String methodName)` Adds to the list of method names used in the search for `Throwable` objects.
`static java.lang.Throwable`	`getCause(java.lang.Throwable throwable)` Introspects the `Throwable` to obtain the cause.
`static java.lang.Throwable`	`getCause(java.lang.Throwable throwable, java.lang.String[] methodNames)` Introspects the `Throwable` to obtain the cause.
`static java.lang.String`	`getFullStackTrace(java.lang.Throwable throwable)` A way to get the entire nested stack-trace of an throwable.
`static java.lang.String`	`getMessage(java.lang.Throwable th)` Gets a short message summarising the exception.
`static java.lang.Throwable`	`getRootCause(java.lang.Throwable throwable)` Introspects the `Throwable` to obtain the root cause.
`static java.lang.String`	`getRootCauseMessage(java.lang.Throwable th)` Gets a short message summarising the root cause exception.
`static java.lang.String[]`	`getRootCauseStackTrace(java.lang.Throwable throwable)` Creates a compact stack trace for the root cause of the supplied `Throwable`.
`static java.lang.String[]`	`getStackFrames(java.lang.Throwable throwable)` Captures the stack trace associated with the specified `Throwable` object, decomposing it into a list of stack frames.
`static java.lang.String`	`getStackTrace(java.lang.Throwable throwable)` Gets the stack trace from a Throwable as a String.
`static int`	`getThrowableCount(java.lang.Throwable throwable)` Counts the number of `Throwable` objects in the exception chain.
`static java.util.List`	`getThrowableList(java.lang.Throwable throwable)` Returns the list of `Throwable` objects in the exception chain.
`static java.lang.Throwable[]`	`getThrowables(java.lang.Throwable throwable)` Returns the list of `Throwable` objects in the exception chain.
`static int`	`indexOfThrowable(java.lang.Throwable throwable, java.lang.Class clazz)` Returns the (zero based) index of the first `Throwable` that matches the specified class (exactly) in the exception chain.
`static int`	`indexOfThrowable(java.lang.Throwable throwable, java.lang.Class clazz, int fromIndex)` Returns the (zero based) index of the first `Throwable` that matches the specified type in the exception chain from a specified index.
`static int`	`indexOfType(java.lang.Throwable throwable, java.lang.Class type)` Returns the (zero based) index of the first `Throwable` that matches the specified class or subclass in the exception chain.
`static int`	`indexOfType(java.lang.Throwable throwable, java.lang.Class type, int fromIndex)` Returns the (zero based) index of the first `Throwable` that matches the specified type in the exception chain from a specified index.
`static boolean`	`isCauseMethodName(java.lang.String methodName)` Tests if the list of method names used in the search for `Throwable` objects include the given name.
`static boolean`	`isNestedThrowable(java.lang.Throwable throwable)` Checks whether this `Throwable` class can store a cause.
`static boolean`	`isThrowableNested()` Checks if the Throwable class has a `getCause` method.
`static void`	`printRootCauseStackTrace(java.lang.Throwable throwable)` Prints a compact stack trace for the root cause of a throwable to `System.err`.
`static void`	`printRootCauseStackTrace(java.lang.Throwable throwable, java.io.PrintStream stream)` Prints a compact stack trace for the root cause of a throwable.
`static void`	`printRootCauseStackTrace(java.lang.Throwable throwable, java.io.PrintWriter writer)` Prints a compact stack trace for the root cause of a throwable.
`static void`	`removeCauseMethodName(java.lang.String methodName)` Removes from the list of method names used in the search for `Throwable` objects.
`static void`	`removeCommonFrames(java.util.List causeFrames, java.util.List wrapperFrames)` Removes common frames from the cause trace given the two stack traces.
`static boolean`	`setCause(java.lang.Throwable target, java.lang.Throwable cause)` Sets the cause of a `Throwable` using introspection, allowing source code compatibility between pre-1.4 and post-1.4 Java releases.

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - ExceptionUtils
```
public ExceptionUtils()
```
    Public constructor allows an instance of ExceptionUtils to be created, although that is not normally necessary.
- Method Detail
  - addCauseMethodName
```
public static void addCauseMethodName(java.lang.String methodName)
```
    Adds to the list of method names used in the search for Throwable objects.
    
    Parameters:
    
    methodName - the methodName to add to the list, null and empty strings are ignored
    
    Since:
    
    2.0
  - removeCauseMethodName
```
public static void removeCauseMethodName(java.lang.String methodName)
```
    Removes from the list of method names used in the search for Throwable objects.
    
    Parameters:
    
    methodName - the methodName to remove from the list, null and empty strings are ignored
    
    Since:
    
    2.1
  - setCause
```
public static boolean setCause(java.lang.Throwable target,
                               java.lang.Throwable cause)
```
    Sets the cause of a Throwable using introspection, allowing source code compatibility between pre-1.4 and post-1.4 Java releases.
    
    The typical use of this method is inside a constructor as in the following example:
```
 import org.apache.commons.lang.exception.ExceptionUtils;
  
 public class MyException extends Exception {
  
    public MyException(String msg) {
       super(msg);
    }

    public MyException(String msg, Throwable cause) {
       super(msg);
       ExceptionUtils.setCause(this, cause);
    }
 }
 
```
    Parameters:
    
    target - the target Throwable
    
    cause - the Throwable to set in the target
    
    Returns:
    
    a true if the target has been modified
    
    Since:
    
    2.2
  - isCauseMethodName
```
public static boolean isCauseMethodName(java.lang.String methodName)
```
    Tests if the list of method names used in the search for Throwable objects include the given name.
    
    Parameters:
    
    methodName - the methodName to search in the list.
    
    Returns:
    
    if the list of method names used in the search for Throwable objects include the given name.
    
    Since:
    
    2.1
  - getCause
```
public static java.lang.Throwable getCause(java.lang.Throwable throwable)
```
    Introspects the Throwable to obtain the cause.
    
    The method searches for methods with specific names that return a Throwable object. This will pick up most wrapping exceptions, including those from JDK 1.4, and NestableException. The method names can be added to using addCauseMethodName(String).
    
    The default list searched for are:
    - getCause()
    - getNextException()
    - getTargetException()
    - getException()
    - getSourceException()
    - getRootCause()
    - getCausedByException()
    - getNested()
    In the absence of any such method, the object is inspected for a detail field assignable to a Throwable.
    
    If none of the above is found, returns null.
    Parameters:
    
    throwable - the throwable to introspect for a cause, may be null
    
    Returns:
    
    the cause of the Throwable, null if none found or null throwable input
    
    Since:
    
    1.0
  - getCause
```
public static java.lang.Throwable getCause(java.lang.Throwable throwable,
                                           java.lang.String[] methodNames)
```
    Introspects the Throwable to obtain the cause.
    1. Try known exception types.
    2. Try the supplied array of method names.
    3. Try the field 'detail'.
    A null set of method names means use the default set. A null in the set of method names will be ignored.
    Parameters:
    
    throwable - the throwable to introspect for a cause, may be null
    
    methodNames - the method names, null treated as default set
    
    Returns:
    
    the cause of the Throwable, null if none found or null throwable input
    
    Since:
    
    1.0
  - getRootCause
```
public static java.lang.Throwable getRootCause(java.lang.Throwable throwable)
```
    Introspects the Throwable to obtain the root cause.
    
    This method walks through the exception chain to the last element, "root" of the tree, using getCause(Throwable), and returns that exception.
    
    From version 2.2, this method handles recursive cause structures that might otherwise cause infinite loops. If the throwable parameter has a cause of itself, then null will be returned. If the throwable parameter cause chain loops, the last element in the chain before the loop is returned.
    
    Parameters:
    
    throwable - the throwable to get the root cause for, may be null
    
    Returns:
    
    the root cause of the Throwable, null if none found or null throwable input
  - isThrowableNested
```
public static boolean isThrowableNested()
```
    Checks if the Throwable class has a getCause method.
    
    This is true for JDK 1.4 and above.
    
    Returns:
    
    true if Throwable is nestable
    
    Since:
    
    2.0
  - isNestedThrowable
```
public static boolean isNestedThrowable(java.lang.Throwable throwable)
```
    Checks whether this Throwable class can store a cause.
    
    This method does not check whether it actually does store a cause.
    
    Parameters:
    
    throwable - the Throwable to examine, may be null
    
    Returns:
    
    boolean true if nested otherwise false
    
    Since:
    
    2.0
  - getThrowableCount
```
public static int getThrowableCount(java.lang.Throwable throwable)
```
    Counts the number of Throwable objects in the exception chain.
    
    A throwable without cause will return 1. A throwable with one cause will return 2 and so on. A null throwable will return 0.
    
    From version 2.2, this method handles recursive cause structures that might otherwise cause infinite loops. The cause chain is processed until the end is reached, or until the next item in the chain is already in the result set.
    
    Parameters:
    
    throwable - the throwable to inspect, may be null
    
    Returns:
    
    the count of throwables, zero if null input
  - getThrowables
```
public static java.lang.Throwable[] getThrowables(java.lang.Throwable throwable)
```
    Returns the list of Throwable objects in the exception chain.
    
    A throwable without cause will return an array containing one element - the input throwable. A throwable with one cause will return an array containing two elements. - the input throwable and the cause throwable. A null throwable will return an array of size zero.
    
    From version 2.2, this method handles recursive cause structures that might otherwise cause infinite loops. The cause chain is processed until the end is reached, or until the next item in the chain is already in the result set.
    
    Parameters:
    
    throwable - the throwable to inspect, may be null
    
    Returns:
    
    the array of throwables, never null
    
    See Also:
    
    getThrowableList(Throwable)
  - getThrowableList
```
public static java.util.List getThrowableList(java.lang.Throwable throwable)
```
    Returns the list of Throwable objects in the exception chain.
    
    A throwable without cause will return a list containing one element - the input throwable. A throwable with one cause will return a list containing two elements. - the input throwable and the cause throwable. A null throwable will return a list of size zero.
    
    This method handles recursive cause structures that might otherwise cause infinite loops. The cause chain is processed until the end is reached, or until the next item in the chain is already in the result set.
    
    Parameters:
    
    throwable - the throwable to inspect, may be null
    
    Returns:
    
    the list of throwables, never null
    
    Since:
    
    Commons Lang 2.2
  - indexOfThrowable
```
public static int indexOfThrowable(java.lang.Throwable throwable,
                                   java.lang.Class clazz)
```
    Returns the (zero based) index of the first Throwable that matches the specified class (exactly) in the exception chain. Subclasses of the specified class do not match - see indexOfType(Throwable, Class) for the opposite.
    
    A null throwable returns -1. A null type returns -1. No match in the chain returns -1.
    
    Parameters:
    
    throwable - the throwable to inspect, may be null
    
    clazz - the class to search for, subclasses do not match, null returns -1
    
    Returns:
    
    the index into the throwable chain, -1 if no match or null input
  - indexOfThrowable
```
public static int indexOfThrowable(java.lang.Throwable throwable,
                                   java.lang.Class clazz,
                                   int fromIndex)
```
    Returns the (zero based) index of the first Throwable that matches the specified type in the exception chain from a specified index. Subclasses of the specified class do not match - see indexOfType(Throwable, Class, int) for the opposite.
    
    A null throwable returns -1. A null type returns -1. No match in the chain returns -1. A negative start index is treated as zero. A start index greater than the number of throwables returns -1.
    
    Parameters:
    
    throwable - the throwable to inspect, may be null
    
    clazz - the class to search for, subclasses do not match, null returns -1
    
    fromIndex - the (zero based) index of the starting position, negative treated as zero, larger than chain size returns -1
    
    Returns:
    
    the index into the throwable chain, -1 if no match or null input
  - indexOfType
```
public static int indexOfType(java.lang.Throwable throwable,
                              java.lang.Class type)
```
    Returns the (zero based) index of the first Throwable that matches the specified class or subclass in the exception chain. Subclasses of the specified class do match - see indexOfThrowable(Throwable, Class) for the opposite.
    
    A null throwable returns -1. A null type returns -1. No match in the chain returns -1.
    
    Parameters:
    
    throwable - the throwable to inspect, may be null
    
    type - the type to search for, subclasses match, null returns -1
    
    Returns:
    
    the index into the throwable chain, -1 if no match or null input
    
    Since:
    
    2.1
  - indexOfType
```
public static int indexOfType(java.lang.Throwable throwable,
                              java.lang.Class type,
                              int fromIndex)
```
    Returns the (zero based) index of the first Throwable that matches the specified type in the exception chain from a specified index. Subclasses of the specified class do match - see indexOfThrowable(Throwable, Class) for the opposite.
    
    A null throwable returns -1. A null type returns -1. No match in the chain returns -1. A negative start index is treated as zero. A start index greater than the number of throwables returns -1.
    
    Parameters:
    
    throwable - the throwable to inspect, may be null
    
    type - the type to search for, subclasses match, null returns -1
    
    fromIndex - the (zero based) index of the starting position, negative treated as zero, larger than chain size returns -1
    
    Returns:
    
    the index into the throwable chain, -1 if no match or null input
    
    Since:
    
    2.1
  - printRootCauseStackTrace
```
public static void printRootCauseStackTrace(java.lang.Throwable throwable)
```
    Prints a compact stack trace for the root cause of a throwable to System.err.
    
    The compact stack trace starts with the root cause and prints stack frames up to the place where it was caught and wrapped. Then it prints the wrapped exception and continues with stack frames until the wrapper exception is caught and wrapped again, etc.
    
    The output of this method is consistent across JDK versions. Note that this is the opposite order to the JDK1.4 display.
    
    The method is equivalent to printStackTrace for throwables that don't have nested causes.
    
    Parameters:
    
    throwable - the throwable to output
    
    Since:
    
    2.0
  - printRootCauseStackTrace
```
public static void printRootCauseStackTrace(java.lang.Throwable throwable,
                                            java.io.PrintStream stream)
```
    Prints a compact stack trace for the root cause of a throwable.
    
    The compact stack trace starts with the root cause and prints stack frames up to the place where it was caught and wrapped. Then it prints the wrapped exception and continues with stack frames until the wrapper exception is caught and wrapped again, etc.
    
    The output of this method is consistent across JDK versions. Note that this is the opposite order to the JDK1.4 display.
    
    The method is equivalent to printStackTrace for throwables that don't have nested causes.
    
    Parameters:
    
    throwable - the throwable to output, may be null
    
    stream - the stream to output to, may not be null
    
    Throws:
    
    java.lang.IllegalArgumentException - if the stream is null
    
    Since:
    
    2.0
  - printRootCauseStackTrace
```
public static void printRootCauseStackTrace(java.lang.Throwable throwable,
                                            java.io.PrintWriter writer)
```
    Prints a compact stack trace for the root cause of a throwable.
    
    The compact stack trace starts with the root cause and prints stack frames up to the place where it was caught and wrapped. Then it prints the wrapped exception and continues with stack frames until the wrapper exception is caught and wrapped again, etc.
    
    The output of this method is consistent across JDK versions. Note that this is the opposite order to the JDK1.4 display.
    
    The method is equivalent to printStackTrace for throwables that don't have nested causes.
    
    Parameters:
    
    throwable - the throwable to output, may be null
    
    writer - the writer to output to, may not be null
    
    Throws:
    
    java.lang.IllegalArgumentException - if the writer is null
    
    Since:
    
    2.0
  - getRootCauseStackTrace
```
public static java.lang.String[] getRootCauseStackTrace(java.lang.Throwable throwable)
```
    Creates a compact stack trace for the root cause of the supplied Throwable.
    
    The output of this method is consistent across JDK versions. It consists of the root exception followed by each of its wrapping exceptions separated by '[wrapped]'. Note that this is the opposite order to the JDK1.4 display.
    
    Parameters:
    
    throwable - the throwable to examine, may be null
    
    Returns:
    
    an array of stack trace frames, never null
    
    Since:
    
    2.0
  - removeCommonFrames
```
public static void removeCommonFrames(java.util.List causeFrames,
                                      java.util.List wrapperFrames)
```
    Removes common frames from the cause trace given the two stack traces.
    
    Parameters:
    
    causeFrames - stack trace of a cause throwable
    
    wrapperFrames - stack trace of a wrapper throwable
    
    Throws:
    
    java.lang.IllegalArgumentException - if either argument is null
    
    Since:
    
    2.0
  - getFullStackTrace
```
public static java.lang.String getFullStackTrace(java.lang.Throwable throwable)
```
    A way to get the entire nested stack-trace of an throwable.
    
    The result of this method is highly dependent on the JDK version and whether the exceptions override printStackTrace or not.
    
    Parameters:
    
    throwable - the Throwable to be examined
    
    Returns:
    
    the nested stack trace, with the root cause first
    
    Since:
    
    2.0
  - getStackTrace
```
public static java.lang.String getStackTrace(java.lang.Throwable throwable)
```
    Gets the stack trace from a Throwable as a String.
    
    The result of this method vary by JDK version as this method uses Throwable.printStackTrace(java.io.PrintWriter). On JDK1.3 and earlier, the cause exception will not be shown unless the specified throwable alters printStackTrace.
    
    Parameters:
    
    throwable - the Throwable to be examined
    
    Returns:
    
    the stack trace as generated by the exception's printStackTrace(PrintWriter) method
  - getStackFrames
```
public static java.lang.String[] getStackFrames(java.lang.Throwable throwable)
```
    Captures the stack trace associated with the specified Throwable object, decomposing it into a list of stack frames.
    
    The result of this method vary by JDK version as this method uses Throwable.printStackTrace(java.io.PrintWriter). On JDK1.3 and earlier, the cause exception will not be shown unless the specified throwable alters printStackTrace.
    
    Parameters:
    
    throwable - the Throwable to examine, may be null
    
    Returns:
    
    an array of strings describing each stack frame, never null
  - getMessage
```
public static java.lang.String getMessage(java.lang.Throwable th)
```
    Gets a short message summarising the exception.
    The message returned is of the form {ClassNameWithoutPackage}: {ThrowableMessage}
    
    Parameters:
    
    th - the throwable to get a message for, null returns empty string
    
    Returns:
    
    the message, non-null
    
    Since:
    
    Commons Lang 2.2
  - getRootCauseMessage
```
public static java.lang.String getRootCauseMessage(java.lang.Throwable th)
```
    Gets a short message summarising the root cause exception.
    The message returned is of the form {ClassNameWithoutPackage}: {ThrowableMessage}
    
    Parameters:
    
    th - the throwable to get a message for, null returns empty string
    
    Returns:
    
    the message, non-null
    
    Since:
    
    Commons Lang 2.2

Class ExceptionUtils

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

ExceptionUtils

Method Detail

addCauseMethodName

removeCauseMethodName

setCause

isCauseMethodName

getCause

getCause

getRootCause

isThrowableNested

isNestedThrowable

getThrowableCount

getThrowables

getThrowableList

indexOfThrowable

indexOfThrowable

indexOfType

indexOfType

printRootCauseStackTrace

printRootCauseStackTrace

printRootCauseStackTrace

getRootCauseStackTrace

removeCommonFrames

getFullStackTrace

getStackTrace

getStackFrames

getMessage

getRootCauseMessage