The Byte class wraps a value of primitive type byte in an object. An object of type Byte contains a single field whose type is byte.

In addition, this class provides several methods for converting a byte to a String and a String to a byte, as well as other constants and methods useful when dealing with a byte.

@author
Nakul Saraiya
@version
1.40, 05/11/04
@since
JDK1.1
Constructs a newly allocated Byte object that represents the specified byte value.
Parameters
valuethe value to be represented by the Byte.
Constructs a newly allocated Byte object that represents the byte value indicated by the String parameter. The string is converted to a byte value in exactly the manner used by the parseByte method for radix 10.
Parameters
sthe String to be converted to a Byte
Throws
NumberFormatExceptionIf the String does not contain a parsable byte.
A constant holding the maximum value a byte can have, 27-1.
A constant holding the minimum value a byte can have, -27.
The number of bits used to represent a byte value in two's complement binary form.
@since
1.5
The Class instance representing the primitive type byte.
Returns the value of this Byte as a byte.
Compares two Byte objects numerically.
Parameters
anotherBytethe Byte to be compared.
Return
the value 0 if this Byte is equal to the argument Byte; a value less than 0 if this Byte is numerically less than the argument Byte; and a value greater than 0 if this Byte is numerically greater than the argument Byte (signed comparison).
@since
1.2
Compares this object with the specified object for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.

In the foregoing description, the notation sgn(expression) designates the mathematical signum function, which is defined to return one of -1, 0, or 1 according to whether the value of expression is negative, zero or positive. The implementor must ensure sgn(x.compareTo(y)) == -sgn(y.compareTo(x)) for all x and y. (This implies that x.compareTo(y) must throw an exception iff y.compareTo(x) throws an exception.)

The implementor must also ensure that the relation is transitive: (x.compareTo(y)>0 && y.compareTo(z)>0) implies x.compareTo(z)>0.

Finally, the implementer must ensure that x.compareTo(y)==0 implies that sgn(x.compareTo(z)) == sgn(y.compareTo(z)), for all z.

It is strongly recommended, but not strictly required that (x.compareTo(y)==0) == (x.equals(y)). Generally speaking, any class that implements the Comparable interface and violates this condition should clearly indicate this fact. The recommended language is "Note: this class has a natural ordering that is inconsistent with equals."

Parameters
othe Object to be compared.
Return
a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.
Throws
ClassCastExceptionif the specified object's type prevents it from being compared to this Object.
Decodes a String into a Byte. Accepts decimal, hexadecimal, and octal numbers given by the following grammar:
DecodableString:
Signopt DecimalNumeral
Signopt 0x HexDigits
Signopt 0X HexDigits
Signopt # HexDigits
Signopt 0 OctalDigits

Sign:
-
DecimalNumeral, HexDigits, and OctalDigits are defined in §3.10.1 of the Java Language Specification.

The sequence of characters following an (optional) negative sign and/or radix specifier ("0x", "0X", "#", or leading zero) is parsed as by the Byte.parseByte method with the indicated radix (10, 16, or 8). This sequence of characters must represent a positive value or a NumberFormatException will be thrown. The result is negated if first character of the specified String is the minus sign. No whitespace characters are permitted in the String.

Parameters
nmthe String to decode.
Return
a Byte object holding the byte value represented by nm
Throws
NumberFormatExceptionif the String does not contain a parsable byte.
Returns the value of this Byte as a double.
Compares this object to the specified object. The result is true if and only if the argument is not null and is a Byte object that contains the same byte value as this object.
Parameters
objthe object to compare with
Return
true if the objects are the same; false otherwise.
Returns the value of this Byte as a float.
Returns the runtime class of an object. That Class object is the object that is locked by static synchronized methods of the represented class.
Return
The java.lang.Class object that represents the runtime class of the object. The result is of type {@code Class} where X is the erasure of the static type of the expression on which getClass is called.
Returns a hash code for this Byte.
Returns the value of this Byte as an int.
Returns the value of this Byte as a long.
Wakes up a single thread that is waiting on this object's monitor. If any threads are waiting on this object, one of them is chosen to be awakened. The choice is arbitrary and occurs at the discretion of the implementation. A thread waits on an object's monitor by calling one of the wait methods.

The awakened thread will not be able to proceed until the current thread relinquishes the lock on this object. The awakened thread will compete in the usual manner with any other threads that might be actively competing to synchronize on this object; for example, the awakened thread enjoys no reliable privilege or disadvantage in being the next thread to lock this object.

This method should only be called by a thread that is the owner of this object's monitor. A thread becomes the owner of the object's monitor in one of three ways:

  • By executing a synchronized instance method of that object.
  • By executing the body of a synchronized statement that synchronizes on the object.
  • For objects of type Class, by executing a synchronized static method of that class.

Only one thread at a time can own an object's monitor.

Throws
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
Wakes up all threads that are waiting on this object's monitor. A thread waits on an object's monitor by calling one of the wait methods.

The awakened threads will not be able to proceed until the current thread relinquishes the lock on this object. The awakened threads will compete in the usual manner with any other threads that might be actively competing to synchronize on this object; for example, the awakened threads enjoy no reliable privilege or disadvantage in being the next thread to lock this object.

This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.

Throws
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
Parses the string argument as a signed decimal byte. The characters in the string must all be decimal digits, except that the first character may be an ASCII minus sign '-' ('\u002D') to indicate a negative value. The resulting byte value is returned, exactly as if the argument and the radix 10 were given as arguments to the method.
Parameters
sa String containing the byte representation to be parsed
Return
the byte value represented by the argument in decimal
Throws
NumberFormatExceptionif the string does not contain a parsable byte.
Parses the string argument as a signed byte in the radix specified by the second argument. The characters in the string must all be digits, of the specified radix (as determined by whether returns a nonnegative value) except that the first character may be an ASCII minus sign '-' ('\u002D') to indicate a negative value. The resulting byte value is returned.

An exception of type NumberFormatException is thrown if any of the following situations occurs:

  • The first argument is null or is a string of length zero.
  • The radix is either smaller than java.lang.Character#MIN_RADIX or larger than java.lang.Character#MAX_RADIX .
  • Any character of the string is not a digit of the specified radix, except that the first character may be a minus sign '-' ('\u002D') provided that the string is longer than length 1.
  • The value represented by the string is not a value of type byte.
Parameters
sthe String containing the byte representation to be parsed
radixthe radix to be used while parsing s
Return
the byte value represented by the string argument in the specified radix
Throws
NumberFormatExceptionIf the string does not contain a parsable byte.
Returns the value of this Byte as a short.
Returns a String object representing this Byte's value. The value is converted to signed decimal representation and returned as a string, exactly as if the byte value were given as an argument to the method.
Return
a string representation of the value of this object in base 10.
Returns a new String object representing the specified byte. The radix is assumed to be 10.
Parameters
bthe byte to be converted
Return
the string representation of the specified byte
Returns a Byte instance representing the specified byte value. If a new Byte instance is not required, this method should generally be used in preference to the constructor , as this method is likely to yield significantly better space and time performance by caching frequently requested values.
Parameters
ba byte value.
Return
a Byte instance representing b.
@since
1.5
Returns a Byte object holding the value given by the specified String. The argument is interpreted as representing a signed decimal byte, exactly as if the argument were given to the method. The result is a Byte object that represents the byte value specified by the string.

In other words, this method returns a Byte object equal to the value of:

new Byte(Byte.parseByte(s))
Parameters
sthe string to be parsed
Return
a Byte object holding the value represented by the string argument
Throws
NumberFormatExceptionIf the String does not contain a parsable byte.
Returns a Byte object holding the value extracted from the specified String when parsed with the radix given by the second argument. The first argument is interpreted as representing a signed byte in the radix specified by the second argument, exactly as if the argument were given to the method. The result is a Byte object that represents the byte value specified by the string.

In other words, this method returns a Byte object equal to the value of:

new Byte(Byte.parseByte(s, radix))
Parameters
sthe string to be parsed
radixthe radix to be used in interpreting s
Return
a Byte object holding the value represented by the string argument in the specified radix.
Throws
NumberFormatExceptionIf the String does not contain a parsable byte.
Causes current thread to wait until another thread invokes the method or the method for this object. In other words, this method behaves exactly as if it simply performs the call wait(0).

The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until another thread notifies threads waiting on this object's monitor to wake up either through a call to the notify method or the notifyAll method. The thread then waits until it can re-obtain ownership of the monitor and resumes execution.

As in the one argument version, interrupts and spurious wakeups are possible, and this method should always be used in a loop:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait();
         ... // Perform action appropriate to condition
     }
 
This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.
Throws
IllegalMonitorStateExceptionif the current thread is not the owner of the object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.
Causes current thread to wait until either another thread invokes the method or the method for this object, or a specified amount of time has elapsed.

The current thread must own this object's monitor.

This method causes the current thread (call it T) to place itself in the wait set for this object and then to relinquish any and all synchronization claims on this object. Thread T becomes disabled for thread scheduling purposes and lies dormant until one of four things happens:

  • Some other thread invokes the notify method for this object and thread T happens to be arbitrarily chosen as the thread to be awakened.
  • Some other thread invokes the notifyAll method for this object.
  • Some other thread interrupts thread T.
  • The specified amount of real time has elapsed, more or less. If timeout is zero, however, then real time is not taken into consideration and the thread simply waits until notified.
The thread T is then removed from the wait set for this object and re-enabled for thread scheduling. It then competes in the usual manner with other threads for the right to synchronize on the object; once it has gained control of the object, all its synchronization claims on the object are restored to the status quo ante - that is, to the situation as of the time that the wait method was invoked. Thread T then returns from the invocation of the wait method. Thus, on return from the wait method, the synchronization state of the object and of thread T is exactly as it was when the wait method was invoked.

A thread can also wake up without being notified, interrupted, or timing out, a so-called spurious wakeup. While this will rarely occur in practice, applications must guard against it by testing for the condition that should have caused the thread to be awakened, and continuing to wait if the condition is not satisfied. In other words, waits should always occur in loops, like this one:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait(timeout);
         ... // Perform action appropriate to condition
     }
 
(For more information on this topic, see Section 3.2.3 in Doug Lea's "Concurrent Programming in Java (Second Edition)" (Addison-Wesley, 2000), or Item 50 in Joshua Bloch's "Effective Java Programming Language Guide" (Addison-Wesley, 2001).

If the current thread is interrupted by another thread while it is waiting, then an InterruptedException is thrown. This exception is not thrown until the lock status of this object has been restored as described above.

Note that the wait method, as it places the current thread into the wait set for this object, unlocks only this object; any other objects on which the current thread may be synchronized remain locked while the thread waits.

This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.

Parameters
timeoutthe maximum time to wait in milliseconds.
Throws
IllegalArgumentExceptionif the value of timeout is negative.
IllegalMonitorStateExceptionif the current thread is not the owner of the object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.
Causes current thread to wait until another thread invokes the method or the method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.

This method is similar to the wait method of one argument, but it allows finer control over the amount of time to wait for a notification before giving up. The amount of real time, measured in nanoseconds, is given by:

 1000000*timeout+nanos

In all other respects, this method does the same thing as the method of one argument. In particular, wait(0, 0) means the same thing as wait(0).

The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until either of the following two conditions has occurred:

  • Another thread notifies threads waiting on this object's monitor to wake up either through a call to the notify method or the notifyAll method.
  • The timeout period, specified by timeout milliseconds plus nanos nanoseconds arguments, has elapsed.

The thread then waits until it can re-obtain ownership of the monitor and resumes execution.

As in the one argument version, interrupts and spurious wakeups are possible, and this method should always be used in a loop:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait(timeout, nanos);
         ... // Perform action appropriate to condition
     }
 
This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.
Parameters
timeoutthe maximum time to wait in milliseconds.
nanosadditional time, in nanoseconds range 0-999999.
Throws
IllegalArgumentExceptionif the value of timeout is negative or the value of nanos is not in the range 0-999999.
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.