Known Direct Subclasses |
Known Indirect Subclasses |
XPathException
represents a generic XPath exception.
Public Constructor Summary
Public Method Summary
Throwable |
getCause()
Returns the cause of this throwable or
null if the
cause is nonexistent or unknown. |
void |
printStackTrace()
Prints this throwable and its backtrace to the
standard error stream.
|
void |
printStackTrace(PrintWriter s)
Prints this throwable and its backtrace to the specified
print writer.
|
void |
printStackTrace(PrintStream s)
Prints this throwable and its backtrace to the specified print stream.
|
Inherited Method Summary
Public Constructors
public XPathException (String message)
Constructs a new XPathException
with the specified detail message
.
The cause
is not initialized.
If message
is null
, then a NullPointerException
is thrown.
Parameters
message | The detail message. |
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public XPathException (Throwable cause)
Constructs a new XPathException
with the specified cause
.
If cause
is null
, then a NullPointerException
is thrown.
Parameters
cause | The cause. |
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Throws
NullPointerException | if cause is null .
|
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Public Methods
public Throwable getCause ()
Returns the cause of this throwable or null
if the
cause is nonexistent or unknown. (The cause is the throwable that
caused this throwable to get thrown.)
This implementation returns the cause that was supplied via one of
the constructors requiring a Throwable
, or that was set after
creation with the initCause(Throwable)
method. While it is
typically unnecessary to override this method, a subclass can override
it to return a cause set by some other means. This is appropriate for
a "legacy chained throwable" that predates the addition of chained
exceptions to Throwable
. Note that it is not
necessary to override any of the PrintStackTrace
methods,
all of which invoke the getCause
method to determine the
cause of a throwable.
Returns
- the cause of this throwable or
null
if the cause is nonexistent or unknown.
public void printStackTrace ()
Prints this throwable and its backtrace to the
standard error stream. This method prints a stack trace for this
Throwable
object on the error output stream that is
the value of the field System.err
. The first line of
output contains the result of the toString()
method for
this object. Remaining lines represent data previously recorded by
the method fillInStackTrace()
. The format of this
information depends on the implementation, but the following
example may be regarded as typical:
This example was produced by running the program:java.lang.NullPointerException at MyClass.mash(MyClass.java:9) at MyClass.crunch(MyClass.java:6) at MyClass.main(MyClass.java:3)
class MyClass { public static void main(String[] args) { crunch(null); } static void crunch(int[] a) { mash(a); } static void mash(int[] b) { System.out.println(b[0]); } }The backtrace for a throwable with an initialized, non-null cause should generally include the backtrace for the cause. The format of this information depends on the implementation, but the following example may be regarded as typical:
HighLevelException: MidLevelException: LowLevelException at Junk.a(Junk.java:13) at Junk.main(Junk.java:4) Caused by: MidLevelException: LowLevelException at Junk.c(Junk.java:23) at Junk.b(Junk.java:17) at Junk.a(Junk.java:11) ... 1 more Caused by: LowLevelException at Junk.e(Junk.java:30) at Junk.d(Junk.java:27) at Junk.c(Junk.java:21) ... 3 moreNote the presence of lines containing the characters
"..."
.
These lines indicate that the remainder of the stack trace for this
exception matches the indicated number of frames from the bottom of the
stack trace of the exception that was caused by this exception (the
"enclosing" exception). This shorthand can greatly reduce the length
of the output in the common case where a wrapped exception is thrown
from same method as the "causative exception" is caught. The above
example was produced by running the program:
public class Junk { public static void main(String args[]) { try { a(); } catch(HighLevelException e) { e.printStackTrace(); } } static void a() throws HighLevelException { try { b(); } catch(MidLevelException e) { throw new HighLevelException(e); } } static void b() throws MidLevelException { c(); } static void c() throws MidLevelException { try { d(); } catch(LowLevelException e) { throw new MidLevelException(e); } } static void d() throws LowLevelException { e(); } static void e() throws LowLevelException { throw new LowLevelException(); } } class HighLevelException extends Exception { HighLevelException(Throwable cause) { super(cause); } } class MidLevelException extends Exception { MidLevelException(Throwable cause) { super(cause); } } class LowLevelException extends Exception { }As of release 7, the platform supports the notion of suppressed exceptions (in conjunction with the
try
-with-resources statement). Any exceptions that were
suppressed in order to deliver an exception are printed out
beneath the stack trace. The format of this information
depends on the implementation, but the following example may be
regarded as typical:
Exception in thread "main" java.lang.Exception: Something happened at Foo.bar(Foo.java:10) at Foo.main(Foo.java:5) Suppressed: Resource$CloseFailException: Resource ID = 0 at Resource.close(Resource.java:26) at Foo.bar(Foo.java:9) ... 1 moreNote that the "... n more" notation is used on suppressed exceptions just at it is used on causes. Unlike causes, suppressed exceptions are indented beyond their "containing exceptions."
An exception can have both a cause and one or more suppressed exceptions:
Exception in thread "main" java.lang.Exception: Main block at Foo3.main(Foo3.java:7) Suppressed: Resource$CloseFailException: Resource ID = 2 at Resource.close(Resource.java:26) at Foo3.main(Foo3.java:5) Suppressed: Resource$CloseFailException: Resource ID = 1 at Resource.close(Resource.java:26) at Foo3.main(Foo3.java:5) Caused by: java.lang.Exception: I did it at Foo3.main(Foo3.java:8)Likewise, a suppressed exception can have a cause:
Exception in thread "main" java.lang.Exception: Main block at Foo4.main(Foo4.java:6) Suppressed: Resource2$CloseFailException: Resource ID = 1 at Resource2.close(Resource2.java:20) at Foo4.main(Foo4.java:5) Caused by: java.lang.Exception: Rats, you caught me at Resource2$CloseFailException.(Resource2.java:45) ... 2 more
public void printStackTrace (PrintWriter s)
Prints this throwable and its backtrace to the specified print writer.
Parameters
s | PrintWriter to use for output |
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public void printStackTrace (PrintStream s)
Prints this throwable and its backtrace to the specified print stream.
Parameters
s | PrintStream to use for output
|
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