Package io.netty.util.internal
Class PlatformDependent
- java.lang.Object
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- io.netty.util.internal.PlatformDependent
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public final class PlatformDependent extends Object
Utility that detects various properties specific to the current runtime environment, such as Java version and the availability of thesun.misc.Unsafe
object.You can disable the use of
sun.misc.Unsafe
if you specify the system property io.netty.noUnsafe.
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Field Summary
Fields Modifier and Type Field Description static boolean
BIG_ENDIAN_NATIVE_ORDER
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static int
addressSize()
Return the address size of the OS.static ByteBuffer
allocateDirectNoCleaner(int capacity)
Allocate a newByteBuffer
with the givencapacity
.static long
allocateMemory(long size)
static byte[]
allocateUninitializedArray(int size)
static int
bitMode()
Returns the bit mode of the current VM (usually 32 or 64.)static long
byteArrayBaseOffset()
static boolean
canEnableTcpNoDelayByDefault()
Returnstrue
if and only if it is fine to enable TCP_NODELAY socket option by default.static void
copyMemory(byte[] src, int srcIndex, byte[] dst, int dstIndex, long length)
static void
copyMemory(byte[] src, int srcIndex, long dstAddr, long length)
static void
copyMemory(long srcAddr, byte[] dst, int dstIndex, long length)
static void
copyMemory(long srcAddr, long dstAddr, long length)
static File
createTempFile(String prefix, String suffix, File directory)
static ByteBuffer
directBuffer(long memoryAddress, int size)
static long
directBufferAddress(ByteBuffer buffer)
static boolean
directBufferPreferred()
Returnstrue
if the platform has reliable low-level direct buffer access API and a user has not specified-Dio.netty.noPreferDirect
option.static boolean
equals(byte[] bytes1, int startPos1, byte[] bytes2, int startPos2, int length)
Compare twobyte
arrays for equality.static int
equalsConstantTime(byte[] bytes1, int startPos1, byte[] bytes2, int startPos2, int length)
Compare twobyte
arrays for equality without leaking timing information.static void
freeDirectBuffer(ByteBuffer buffer)
Try to deallocate the specified directByteBuffer
.static void
freeDirectNoCleaner(ByteBuffer buffer)
This method MUST only be called forByteBuffer
s that were allocated viaallocateDirectNoCleaner(int)
.static void
freeMemory(long address)
static byte
getByte(byte[] data, int index)
static byte
getByte(byte[] data, long index)
static byte
getByte(long address)
static ClassLoader
getClassLoader(Class<?> clazz)
Return theClassLoader
for the givenClass
.static ClassLoader
getContextClassLoader()
Return the contextClassLoader
for the currentThread
.static int
getInt(byte[] data, int index)
static int
getInt(int[] data, long index)
static int
getInt(long address)
static int
getInt(Object object, long fieldOffset)
static int
getIntVolatile(long address)
static long
getLong(byte[] data, int index)
static long
getLong(long address)
static long
getLong(long[] data, long index)
static Object
getObject(Object object, long fieldOffset)
static short
getShort(byte[] data, int index)
static short
getShort(long address)
static ClassLoader
getSystemClassLoader()
Return the systemClassLoader
.static Throwable
getUnsafeUnavailabilityCause()
Return the reason (if any) whysun.misc.Unsafe
was not available.static boolean
hasDirectBufferNoCleanerConstructor()
static int
hashCodeAscii(byte[] bytes, int startPos, int length)
Calculate a hash code of a byte array assuming ASCII character encoding.static int
hashCodeAscii(CharSequence bytes)
Calculate a hash code of a byte array assuming ASCII character encoding.static boolean
hasUnsafe()
Returntrue
ifsun.misc.Unsafe
was found on the classpath and can be used for accelerated direct memory access.static boolean
isAndroid()
Returnstrue
if and only if the current platform is Androidstatic boolean
isIkvmDotNet()
static boolean
isJ9Jvm()
static boolean
isOsx()
Returntrue
if the JVM is running on OSX / MacOSstatic boolean
isUnaligned()
true
if and only if the platform supports unaligned access.static boolean
isWindows()
Returntrue
if the JVM is running on Windowsstatic boolean
isZero(byte[] bytes, int startPos, int length)
Determine if a subsection of an array is zero.static int
javaVersion()
Return the version of Java under which this library is used.static long
maxDirectMemory()
Returns the maximum memory reserved for direct buffer allocation.static boolean
maybeSuperUser()
Returntrue
if the current user may be a super-user.static <C> Deque<C>
newConcurrentDeque()
Returns a new concurrentDeque
.static <K,V>
ConcurrentMap<K,V>newConcurrentHashMap()
Creates a new fastestConcurrentMap
implementation for the current platform.static <K,V>
ConcurrentMap<K,V>newConcurrentHashMap(int initialCapacity)
Creates a new fastestConcurrentMap
implementation for the current platform.static <K,V>
ConcurrentMap<K,V>newConcurrentHashMap(int initialCapacity, float loadFactor)
Creates a new fastestConcurrentMap
implementation for the current platform.static <K,V>
ConcurrentMap<K,V>newConcurrentHashMap(int initialCapacity, float loadFactor, int concurrencyLevel)
Creates a new fastestConcurrentMap
implementation for the current platform.static <K,V>
ConcurrentMap<K,V>newConcurrentHashMap(Map<? extends K,? extends V> map)
Creates a new fastestConcurrentMap
implementation for the current platform.static <T> Queue<T>
newFixedMpscQueue(int capacity)
Create a newQueue
which is safe to use for multiple producers (different threads) and a single consumer (one thread!) with the given fixescapacity
.static LongCounter
newLongCounter()
Creates a new fastestLongCounter
implementation for the current platform.static <T> Queue<T>
newMpscQueue()
Create a newQueue
which is safe to use for multiple producers (different threads) and a single consumer (one thread!).static <T> Queue<T>
newMpscQueue(int maxCapacity)
Create a newQueue
which is safe to use for multiple producers (different threads) and a single consumer (one thread!).static <T> Queue<T>
newSpscQueue()
Create a newQueue
which is safe to use for single producer (one thread!) and a single consumer (one thread!).static String
normalizedArch()
static Set<String>
normalizedLinuxClassifiers()
static String
normalizedOs()
static long
objectFieldOffset(Field field)
static void
putByte(byte[] data, int index, byte value)
static void
putByte(long address, byte value)
static void
putByte(Object data, long offset, byte value)
static void
putInt(byte[] data, int index, int value)
static void
putInt(long address, int value)
static void
putIntOrdered(long adddress, int newValue)
static void
putLong(byte[] data, int index, long value)
static void
putLong(long address, long value)
static void
putObject(Object o, long offset, Object x)
static void
putShort(byte[] data, int index, short value)
static void
putShort(long address, short value)
static ByteBuffer
reallocateDirectNoCleaner(ByteBuffer buffer, int capacity)
Reallocate a newByteBuffer
with the givencapacity
.static long
reallocateMemory(long address, long newSize)
static void
setMemory(byte[] dst, int dstIndex, long bytes, byte value)
static void
setMemory(long address, long bytes, byte value)
static Random
threadLocalRandom()
Return aRandom
which is not-threadsafe and so can only be used from the same thread.static void
throwException(Throwable t)
Raises an exception bypassing compiler checks for checked exceptions.static File
tmpdir()
Returns the temporary directory.static long
usedDirectMemory()
Returns the current memory reserved for direct buffer allocation.static boolean
useDirectBufferNoCleaner()
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Method Detail
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byteArrayBaseOffset
public static long byteArrayBaseOffset()
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hasDirectBufferNoCleanerConstructor
public static boolean hasDirectBufferNoCleanerConstructor()
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allocateUninitializedArray
public static byte[] allocateUninitializedArray(int size)
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isAndroid
public static boolean isAndroid()
Returnstrue
if and only if the current platform is Android
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isWindows
public static boolean isWindows()
Returntrue
if the JVM is running on Windows
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isOsx
public static boolean isOsx()
Returntrue
if the JVM is running on OSX / MacOS
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maybeSuperUser
public static boolean maybeSuperUser()
Returntrue
if the current user may be a super-user. Be aware that this is just an hint and so it may return false-positives.
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javaVersion
public static int javaVersion()
Return the version of Java under which this library is used.
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canEnableTcpNoDelayByDefault
public static boolean canEnableTcpNoDelayByDefault()
Returnstrue
if and only if it is fine to enable TCP_NODELAY socket option by default.
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hasUnsafe
public static boolean hasUnsafe()
Returntrue
ifsun.misc.Unsafe
was found on the classpath and can be used for accelerated direct memory access.
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getUnsafeUnavailabilityCause
public static Throwable getUnsafeUnavailabilityCause()
Return the reason (if any) whysun.misc.Unsafe
was not available.
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isUnaligned
public static boolean isUnaligned()
true
if and only if the platform supports unaligned access.- See Also:
- Wikipedia on segfault
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directBufferPreferred
public static boolean directBufferPreferred()
Returnstrue
if the platform has reliable low-level direct buffer access API and a user has not specified-Dio.netty.noPreferDirect
option.
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maxDirectMemory
public static long maxDirectMemory()
Returns the maximum memory reserved for direct buffer allocation.
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usedDirectMemory
public static long usedDirectMemory()
Returns the current memory reserved for direct buffer allocation. This method returns -1 in case that a value is not available.- See Also:
maxDirectMemory()
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tmpdir
public static File tmpdir()
Returns the temporary directory.
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bitMode
public static int bitMode()
Returns the bit mode of the current VM (usually 32 or 64.)
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addressSize
public static int addressSize()
Return the address size of the OS. 4 (for 32 bits systems ) and 8 (for 64 bits systems).
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allocateMemory
public static long allocateMemory(long size)
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freeMemory
public static void freeMemory(long address)
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reallocateMemory
public static long reallocateMemory(long address, long newSize)
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throwException
public static void throwException(Throwable t)
Raises an exception bypassing compiler checks for checked exceptions.
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newConcurrentHashMap
public static <K,V> ConcurrentMap<K,V> newConcurrentHashMap()
Creates a new fastestConcurrentMap
implementation for the current platform.
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newLongCounter
public static LongCounter newLongCounter()
Creates a new fastestLongCounter
implementation for the current platform.
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newConcurrentHashMap
public static <K,V> ConcurrentMap<K,V> newConcurrentHashMap(int initialCapacity)
Creates a new fastestConcurrentMap
implementation for the current platform.
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newConcurrentHashMap
public static <K,V> ConcurrentMap<K,V> newConcurrentHashMap(int initialCapacity, float loadFactor)
Creates a new fastestConcurrentMap
implementation for the current platform.
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newConcurrentHashMap
public static <K,V> ConcurrentMap<K,V> newConcurrentHashMap(int initialCapacity, float loadFactor, int concurrencyLevel)
Creates a new fastestConcurrentMap
implementation for the current platform.
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newConcurrentHashMap
public static <K,V> ConcurrentMap<K,V> newConcurrentHashMap(Map<? extends K,? extends V> map)
Creates a new fastestConcurrentMap
implementation for the current platform.
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freeDirectBuffer
public static void freeDirectBuffer(ByteBuffer buffer)
Try to deallocate the specified directByteBuffer
. Please note this method does nothing if the current platform does not support this operation or the specified buffer is not a direct buffer.
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directBufferAddress
public static long directBufferAddress(ByteBuffer buffer)
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directBuffer
public static ByteBuffer directBuffer(long memoryAddress, int size)
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getInt
public static int getInt(Object object, long fieldOffset)
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getIntVolatile
public static int getIntVolatile(long address)
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putIntOrdered
public static void putIntOrdered(long adddress, int newValue)
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getByte
public static byte getByte(long address)
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getShort
public static short getShort(long address)
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getInt
public static int getInt(long address)
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getLong
public static long getLong(long address)
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getByte
public static byte getByte(byte[] data, int index)
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getByte
public static byte getByte(byte[] data, long index)
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getShort
public static short getShort(byte[] data, int index)
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getInt
public static int getInt(byte[] data, int index)
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getInt
public static int getInt(int[] data, long index)
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getLong
public static long getLong(byte[] data, int index)
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getLong
public static long getLong(long[] data, long index)
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putByte
public static void putByte(long address, byte value)
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putShort
public static void putShort(long address, short value)
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putInt
public static void putInt(long address, int value)
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putLong
public static void putLong(long address, long value)
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putByte
public static void putByte(byte[] data, int index, byte value)
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putByte
public static void putByte(Object data, long offset, byte value)
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putShort
public static void putShort(byte[] data, int index, short value)
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putInt
public static void putInt(byte[] data, int index, int value)
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putLong
public static void putLong(byte[] data, int index, long value)
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objectFieldOffset
public static long objectFieldOffset(Field field)
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copyMemory
public static void copyMemory(long srcAddr, long dstAddr, long length)
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copyMemory
public static void copyMemory(byte[] src, int srcIndex, long dstAddr, long length)
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copyMemory
public static void copyMemory(byte[] src, int srcIndex, byte[] dst, int dstIndex, long length)
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copyMemory
public static void copyMemory(long srcAddr, byte[] dst, int dstIndex, long length)
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setMemory
public static void setMemory(byte[] dst, int dstIndex, long bytes, byte value)
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setMemory
public static void setMemory(long address, long bytes, byte value)
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allocateDirectNoCleaner
public static ByteBuffer allocateDirectNoCleaner(int capacity)
Allocate a newByteBuffer
with the givencapacity
.ByteBuffer
s allocated with this method MUST be deallocated viafreeDirectNoCleaner(ByteBuffer)
.
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reallocateDirectNoCleaner
public static ByteBuffer reallocateDirectNoCleaner(ByteBuffer buffer, int capacity)
Reallocate a newByteBuffer
with the givencapacity
.ByteBuffer
s reallocated with this method MUST be deallocated viafreeDirectNoCleaner(ByteBuffer)
.
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freeDirectNoCleaner
public static void freeDirectNoCleaner(ByteBuffer buffer)
This method MUST only be called forByteBuffer
s that were allocated viaallocateDirectNoCleaner(int)
.
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useDirectBufferNoCleaner
public static boolean useDirectBufferNoCleaner()
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equals
public static boolean equals(byte[] bytes1, int startPos1, byte[] bytes2, int startPos2, int length)
Compare twobyte
arrays for equality. For performance reasons no bounds checking on the parameters is performed.- Parameters:
bytes1
- the first byte array.startPos1
- the position (inclusive) to start comparing inbytes1
.bytes2
- the second byte array.startPos2
- the position (inclusive) to start comparing inbytes2
.length
- the amount of bytes to compare. This is assumed to be validated as not going out of bounds by the caller.
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isZero
public static boolean isZero(byte[] bytes, int startPos, int length)
Determine if a subsection of an array is zero.- Parameters:
bytes
- The byte array.startPos
- The starting index (inclusive) inbytes
.length
- The amount of bytes to check for zero.- Returns:
false
ifbytes[startPos:startsPos+length)
contains a value other than zero.
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equalsConstantTime
public static int equalsConstantTime(byte[] bytes1, int startPos1, byte[] bytes2, int startPos2, int length)
Compare twobyte
arrays for equality without leaking timing information. For performance reasons no bounds checking on the parameters is performed.The
int
return type is intentional and is designed to allow cascading of constant time operations:byte[] s1 = new {1, 2, 3}; byte[] s2 = new {1, 2, 3}; byte[] s3 = new {1, 2, 3}; byte[] s4 = new {4, 5, 6}; boolean equals = (equalsConstantTime(s1, 0, s2, 0, s1.length) & equalsConstantTime(s3, 0, s4, 0, s3.length)) != 0;
- Parameters:
bytes1
- the first byte array.startPos1
- the position (inclusive) to start comparing inbytes1
.bytes2
- the second byte array.startPos2
- the position (inclusive) to start comparing inbytes2
.length
- the amount of bytes to compare. This is assumed to be validated as not going out of bounds by the caller.- Returns:
0
if not equal.1
if equal.
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hashCodeAscii
public static int hashCodeAscii(byte[] bytes, int startPos, int length)
Calculate a hash code of a byte array assuming ASCII character encoding. The resulting hash code will be case insensitive.- Parameters:
bytes
- The array which contains the data to hash.startPos
- What index to start generating a hash code inbytes
length
- The amount of bytes that should be accounted for in the computation.- Returns:
- The hash code of
bytes
assuming ASCII character encoding. The resulting hash code will be case insensitive.
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hashCodeAscii
public static int hashCodeAscii(CharSequence bytes)
Calculate a hash code of a byte array assuming ASCII character encoding. The resulting hash code will be case insensitive.This method assumes that
bytes
is equivalent to abyte[]
but just usingCharSequence
for storage. The upper most byte of eachchar
frombytes
is ignored.- Parameters:
bytes
- The array which contains the data to hash (assumed to be equivalent to abyte[]
).- Returns:
- The hash code of
bytes
assuming ASCII character encoding. The resulting hash code will be case insensitive.
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newMpscQueue
public static <T> Queue<T> newMpscQueue()
Create a newQueue
which is safe to use for multiple producers (different threads) and a single consumer (one thread!).- Returns:
- A MPSC queue which may be unbounded.
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newMpscQueue
public static <T> Queue<T> newMpscQueue(int maxCapacity)
Create a newQueue
which is safe to use for multiple producers (different threads) and a single consumer (one thread!).
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newSpscQueue
public static <T> Queue<T> newSpscQueue()
Create a newQueue
which is safe to use for single producer (one thread!) and a single consumer (one thread!).
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newFixedMpscQueue
public static <T> Queue<T> newFixedMpscQueue(int capacity)
Create a newQueue
which is safe to use for multiple producers (different threads) and a single consumer (one thread!) with the given fixescapacity
.
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getClassLoader
public static ClassLoader getClassLoader(Class<?> clazz)
Return theClassLoader
for the givenClass
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getContextClassLoader
public static ClassLoader getContextClassLoader()
Return the contextClassLoader
for the currentThread
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getSystemClassLoader
public static ClassLoader getSystemClassLoader()
Return the systemClassLoader
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threadLocalRandom
public static Random threadLocalRandom()
Return aRandom
which is not-threadsafe and so can only be used from the same thread.
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isJ9Jvm
public static boolean isJ9Jvm()
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isIkvmDotNet
public static boolean isIkvmDotNet()
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normalizedArch
public static String normalizedArch()
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normalizedOs
public static String normalizedOs()
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createTempFile
public static File createTempFile(String prefix, String suffix, File directory) throws IOException
- Throws:
IOException
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