Jvm (OpenHFT/Chronicle-Core 2.21ea17 API)

java.lang.Object
- java.lang.Enum<Jvm>
- - net.openhft.chronicle.core.Jvm

All Implemented Interfaces:

Serializable, Comparable<Jvm>
```
public enum Jvm
extends Enum<Jvm>
```
Utility class to access information in the JVM.

Field Summary

Fields
Modifier and Type Field and Description

static String JAVA_CLASS_PATH

static String SYSTEM_PROPERTIES

Fields
Modifier and Type	Field and Description
`static String`	`JAVA_CLASS_PATH`
`static String`	`SYSTEM_PROPERTIES`

Method Summary

All Methods Static Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`static long`	`address(@NotNull ByteBuffer byteBuffer)` Returns the native address of the provided `byteBuffer`.
`static void`	`addToClassPath(@NotNull Class<?> clazz)` Ensures that all the jars and other resources are added to the class path of the classloader associated by the provided `clazz`.
`static boolean`	`areOptionalSafepointsEnabled()`
`static int`	`arrayByteBaseOffset()` Returns the array byte base offset used by this JVM.
`static void`	`busyWaitMicros(long durationUs)` Pause in a busy loop for the provided `durationUs` microseconds.
`static void`	`busyWaitUntil(long waitUntilNs)` Pauses the current thread in a busy loop until the provided `waitUntilNs` time is reached.
`static @NotNull ClassMetrics`	`classMetrics(Class<?> clazz)` Acquires and returns the ClassMetrics for the provided `clazz`.
`static int`	`compileThreshold()` Returns the compile threshold for the JVM or else an estimate thereof (e.g.
`static @NotNull ExceptionHandler`	`debug()`
`static void`	`disableDebugHandler()`
`static void`	`doNotCloseOnInterrupt(Class<?> clazz, FileChannel fc)` Employs a best-effort of preventing the provided `fc` from being automatically closed whenever the current thread gets interrupted.
`static boolean`	`dontChain(Class<?> tClass)`
`static void`	`dumpException(@NotNull Map<ExceptionKey,Integer> exceptions)`
`static @NotNull ExceptionHandler`	`error()`
`static @NotNull ExceptionHandler`	`fatal()` Deprecated. use `error()`
`static boolean`	`getBoolean(String systemPropertyKey)` Returns if a System Property with the provided `systemPropertyKey` either exists, is set to "yes" or is set to "true".
`static boolean`	`getBoolean(String systemPropertyKey, boolean defaultValue)` Returns if a System Property with the provided `systemPropertyKey` either exists, is set to "yes" or is set to "true" or, if it does not exist, returns the provided `defaultValue`.
`static double`	`getDouble(String systemPropertyKey, double defaultValue)` Returns the System Property associated with the provided `systemPropertyKey` parsed as a `double` or, if no such parsable System Property exists, returns the provided `defaultValue`.
`static @NotNull Field`	`getField(@NotNull Class<?> clazz, @NotNull String fieldName)` Returns the Field for the provided `clazz` and the provided `fieldName` or throws an Exception if no such Field exists.
`static @Nullable Field`	`getFieldOrNull(@NotNull Class<?> clazz, @NotNull String fieldName)` Returns the Field for the provided `clazz` and the provided `fieldName` or `null` if no such Field exists.
`static @NotNull Method`	`getMethod(@NotNull Class<?> clazz, @NotNull String methodName, Class... argTypes)` Returns the Method for the provided `clazz`, `methodName` and `argTypes` or throws an Exception.
`static int`	`getProcessId()` Returns the current process id or, if the process id cannot be determined, a non-negative random number less than 2^16.
`static long`	`getSize(String property, long defaultValue)` Uses Jvm.parseSize to parse a system property or returns defaultValue if not present, empty or unparseable.
`static <V> V`	`getValue(@NotNull Object target, @NotNull String fieldName)` Returns the value of the provided `fieldName` extracted from the provided `target`.
`static boolean`	`hasException(@NotNull Map<ExceptionKey,Integer> exceptions)`
`static void`	`init()`
`static boolean`	`is64bit()` Returns if the JVM runs in 64 bit mode.
`static boolean`	`isArm()` Returns if the JVM runs on a CPU using the ARM architecture.
`static boolean`	`isAzulZing()`
`static boolean`	`isCodeCoverage()` Returns if the JVM is running in code coverage mode.
`static boolean`	`isDebug()` Returns if the JVM is running in debug mode.
`static boolean`	`isDebugEnabled(Class<?> aClass)`
`static boolean`	`isFlightRecorder()` Returns if the JVM is running in flight recorder mode.
`static boolean`	`isJava12Plus()` Returns if the major Java version is 12 or higher.
`static boolean`	`isJava14Plus()` Returns if the major Java version is 14 or higher.
`static boolean`	`isJava9Plus()` Returns if the major Java version is 9 or higher.
`static boolean`	`isProcessAlive(long pid)` Returns if a process with the provided `pid` process id is alive.
`static boolean`	`isResourceTracing()` Returns if certain chronicle resources (such as memory regions) are traced.
`static String`	`lockWithStack(@NotNull ReentrantLock lock)` Log the stack trace of the thread holding a lock.
`static int`	`majorVersion()` Returns the major Java version (e.g.
`static long`	`maxDirectMemory()` Returns the maximum direct memory in bytes that can ever be allocated or 0 if the value cannot be determined.
`static void`	`nanoPause()` Pause in a busy loop for a very short time.
`static int`	`objectHeaderSize()`
`static void`	`optionalSafepoint()` Deprecated.
`static long`	`parseSize(@NotNull String value)` Parse a string as a decimal memory size with an optional scale.
`static void`	`pause(long durationMs)` Silently pause for the provided `durationMs` milliseconds.
`static @NotNull ExceptionHandler`	`perf()`
`static @NotNull Map<ExceptionKey,Integer>`	`recordExceptions()`
`static @NotNull Map<ExceptionKey,Integer>`	`recordExceptions(boolean debug)`
`static @NotNull Map<ExceptionKey,Integer>`	`recordExceptions(boolean debug, boolean exceptionsOnly)`
`static @NotNull Map<ExceptionKey,Integer>`	`recordExceptions(boolean debug, boolean exceptionsOnly, boolean logToSlf4j)`
`static void`	`resetExceptionHandlers()`
`static <T extends Throwable> @NotNull RuntimeException`	`rethrow(Throwable throwable)` Cast any Throwable (e.g.
`static void`	`safepoint()` Inserts a low-cost Java safe-point in the code path.
`static void`	`setAccessible(@NotNull AccessibleObject accessibleObject)` Set the accessible flag for the provided `accessibleObject` indicating that the reflected object should suppress Java language access checking when it is used.
`static void`	`setExceptionHandlers(@Nullable ExceptionHandler fatal, @Nullable ExceptionHandler warn, @Nullable ExceptionHandler debug)`
`static void`	`setExceptionHandlers(@Nullable ExceptionHandler fatal, @Nullable ExceptionHandler warn, @Nullable ExceptionHandler debug, @Nullable ExceptionHandler perf)`
`static void`	`setExceptionHandlers(@Nullable ExceptionHandler fatal, @Nullable ExceptionHandler error, @Nullable ExceptionHandler warn, @Nullable ExceptionHandler debug, @Nullable ExceptionHandler perf)`
`static void`	`setExceptionsHandlers(@Nullable ExceptionHandler fatal, @Nullable ExceptionHandler warn, @Nullable ExceptionHandler debug)` Deprecated.
`static void`	`setThreadLocalExceptionHandlers(@Nullable ExceptionHandler fatal, @Nullable ExceptionHandler warn, @Nullable ExceptionHandler debug)`
`static void`	`setThreadLocalExceptionHandlers(@Nullable ExceptionHandler fatal, @Nullable ExceptionHandler warn, @Nullable ExceptionHandler debug, @Nullable ExceptionHandler perf)`
`static void`	`setThreadLocalExceptionHandlers(@Nullable ExceptionHandler fatal, @Nullable ExceptionHandler error, @Nullable ExceptionHandler warn, @Nullable ExceptionHandler debug, @Nullable ExceptionHandler perf)`
`static void`	`signalHandler(sun.misc.SignalHandler signalHandler)` Adds the provided `signalHandler` to an internal chain of handlers that will be invoked upon detecting system signals (e.g.
`static boolean`	`stackTraceEndsWith(String endsWith, int maxDepth)` Returns if there is a class name that ends with the provided `endsWith` string when examining the current stack trace of depth at most up to the provided `maxDepth`.
`static @NotNull ExceptionHandler`	`startup()`
`static int`	`trimLast(int first, @NotNull StackTraceElement[] stes)`
`static void`	`trimStackTrace(@NotNull StringBuilder stringBuilder, StackTraceElement... stackTraceElements)` Append the provided `StackTraceElements` to the provided `stringBuilder` trimming some internal methods.
`static long`	`usedDirectMemory()` Returns the accumulated amount of memory in bytes used by direct ByteBuffers or 0 if the value cannot be determined.
`static long`	`usedNativeMemory()` Returns the accumulated amount of memory used in bytes by UnsafeMemory.allocate().
`static @NotNull String`	`userHome()` Returns the user's home directory (e.g.
`static Jvm`	`valueOf(String name)` Returns the enum constant of this type with the specified name.
`static Jvm[]`	`values()` Returns an array containing the constants of this enum type, in the order they are declared.
`static @NotNull ExceptionHandler`	`warn()`

Methods inherited from class java.lang.Enum
clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

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

- Field Detail
  - JAVA_CLASS_PATH
```
public static final String JAVA_CLASS_PATH
```
    See Also:
    
    Constant Field Values
  - SYSTEM_PROPERTIES
```
public static final String SYSTEM_PROPERTIES
```
    See Also:
    
    Constant Field Values
- Method Detail
  - values
```
public static Jvm[] values()
```
    Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:
```
for (Jvm c : Jvm.values())
    System.out.println(c);
```
    Returns:
    
    an array containing the constants of this enum type, in the order they are declared
  - valueOf
```
public static Jvm valueOf(String name)
```
    Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
    
    Parameters:
    
    name - the name of the enum constant to be returned.
    
    Returns:
    
    the enum constant with the specified name
    
    Throws:
    
    IllegalArgumentException - if this enum type has no constant with the specified name
    
    NullPointerException - if the argument is null
  - init
```
public static void init()
```
  - compileThreshold
```
public static int compileThreshold()
```
    Returns the compile threshold for the JVM or else an estimate thereof (e.g. 10_000).
    The compile threshold can be explicitly set using the command line parameter "-XX:CompileThreshold="
    
    Returns:
    
    the compile threshold for the JVM or else an estimate thereof (e.g. 10_000)
  - majorVersion
```
public static int majorVersion()
```
    Returns the major Java version (e.g. 8, 11 or 17)
    
    Returns:
    
    the major Java version (e.g. 8, 11 or 17)
  - isJava9Plus
```
public static boolean isJava9Plus()
```
    Returns if the major Java version is 9 or higher.
    
    Returns:
    
    if the major Java version is 9 or higher
  - isJava12Plus
```
public static boolean isJava12Plus()
```
    Returns if the major Java version is 12 or higher.
    
    Returns:
    
    if the major Java version is 12 or higher
  - isJava14Plus
```
public static boolean isJava14Plus()
```
    Returns if the major Java version is 14 or higher.
    
    Returns:
    
    if the major Java version is 14 or higher
  - getProcessId
```
public static int getProcessId()
```
    Returns the current process id or, if the process id cannot be determined, a non-negative random number less than 2^16.
    
    Returns:
    
    the current process id or, if the process id cannot be determined, a non-negative random number less than 2^16
  - rethrow
```
@NotNull
public static <T extends Throwable> @NotNull RuntimeException rethrow(Throwable throwable)
                                                                        throws T extends Throwable
```
    Cast any Throwable (e.g. a checked exception) to a RuntimeException.
    
    Type Parameters:
    
    T - the type of the Throwable
    
    Parameters:
    
    throwable - to cast
    
    Returns:
    
    this method will never return a Throwable instance, it will just throw it.
    
    Throws:
    
    T - the throwable as an unchecked throwable
    
    T extends Throwable
  - trimStackTrace
```
public static void trimStackTrace(@NotNull
                                  @NotNull StringBuilder stringBuilder,
                                  @NotNull
                                  StackTraceElement... stackTraceElements)
```
    Append the provided StackTraceElements to the provided stringBuilder trimming some internal methods.
    
    Parameters:
    
    stringBuilder - to append to
    
    stackTraceElements - stack trace elements
  - trimLast
```
public static int trimLast(int first,
                           @NotNull
                           @NotNull StackTraceElement[] stes)
```
  - isDebug
```
public static boolean isDebug()
```
    Returns if the JVM is running in debug mode.
    
    Returns:
    
    if the JVM is running in debug mode
  - isFlightRecorder
```
public static boolean isFlightRecorder()
```
    Returns if the JVM is running in flight recorder mode.
    
    Returns:
    
    if the JVM is running in flight recorder mode
  - isCodeCoverage
```
public static boolean isCodeCoverage()
```
    Returns if the JVM is running in code coverage mode.
    
    Returns:
    
    if the JVM is running in code coverage mode
  - pause
```
public static void pause(long durationMs)
```
    Silently pause for the provided durationMs milliseconds.
    If the provided durationMs is positive, then the current thread sleeps.
    If the provided durationMs is zero, then the current thread yields.
    
    Parameters:
    
    durationMs - to sleep for.
  - nanoPause
```
public static void nanoPause()
```
    Pause in a busy loop for a very short time.
  - busyWaitMicros
```
public static void busyWaitMicros(long durationUs)
```
    Pause in a busy loop for the provided durationUs microseconds.
    This method is designed to be used when the time to be waited is very small, typically under a millisecond (@{code durationUs < 1_000}).
    
    Parameters:
    
    durationUs - Time in durationUs
  - busyWaitUntil
```
public static void busyWaitUntil(long waitUntilNs)
```
    Pauses the current thread in a busy loop until the provided waitUntilNs time is reached.
    This method is designed to be used when the time to be waited is very small, typically under a millisecond (@{code durationNs < 1_000_000}).
    
    Parameters:
    
    waitUntilNs - nanosecond precision counter value to await.
  - getField
```
@NotNull
public static @NotNull Field getField(@NotNull
                                               @NotNull Class<?> clazz,
                                               @NotNull
                                               @NotNull String fieldName)
```
    Returns the Field for the provided clazz and the provided fieldName or throws an Exception if no such Field exists.
    
    Parameters:
    
    clazz - to get the field for
    
    fieldName - of the field
    
    Returns:
    
    the Field.
    
    Throws:
    
    AssertionError - if no such Field exists
  - getFieldOrNull
```
@Nullable
public static @Nullable Field getFieldOrNull(@NotNull
                                                       @NotNull Class<?> clazz,
                                                       @NotNull
                                                       @NotNull String fieldName)
```
    Returns the Field for the provided clazz and the provided fieldName or null if no such Field exists.
    
    Parameters:
    
    clazz - to get the field for
    
    fieldName - of the field
    
    Returns:
    
    the Field.
    
    Throws:
    
    AssertionError - if no such Field exists
  - getMethod
```
@NotNull
public static @NotNull Method getMethod(@NotNull
                                                 @NotNull Class<?> clazz,
                                                 @NotNull
                                                 @NotNull String methodName,
                                                 Class... argTypes)
```
    Returns the Method for the provided clazz, methodName and argTypes or throws an Exception.
    if it exists or throws AssertionError.
    Default methods are not detected unless the class explicitly overrides it
    
    Parameters:
    
    clazz - class
    
    methodName - methodName
    
    argTypes - argument types
    
    Returns:
    
    method
    
    Throws:
    
    AssertionError - if no such Method exists
  - setAccessible
```
public static void setAccessible(@NotNull
                                 @NotNull AccessibleObject accessibleObject)
```
    Set the accessible flag for the provided accessibleObject indicating that the reflected object should suppress Java language access checking when it is used.
    The setting of the accessible flag might be subject to security manager approval.
    
    Parameters:
    
    accessibleObject - to modify
    
    Throws:
    
    SecurityException - – if the request is denied.
    
    See Also:
    
    SecurityManager.checkPermission(java.security.Permission), RuntimePermission
  - getValue
```
@Nullable
public static <V> V getValue(@NotNull
                                       @NotNull Object target,
                                       @NotNull
                                       @NotNull String fieldName)
```
    Returns the value of the provided fieldName extracted from the provided target.
    The provided fieldName can denote fields of arbitrary depth (e.g. foo.bar.baz, whereby the foo value will be extracted from the provided target and then the bar value will be extracted from the foo value and so on).
    
    Type Parameters:
    
    V - return type
    
    Parameters:
    
    target - used for extraction
    
    fieldName - denoting the field(s) to extract
    
    Returns:
    
    the value of the provided fieldName extracted from the provided target
  - lockWithStack
```
public static String lockWithStack(@NotNull
                                   @NotNull ReentrantLock lock)
```
    Log the stack trace of the thread holding a lock.
    
    Parameters:
    
    lock - to log
    
    Returns:
    
    the lock.toString plus a stack trace.
  - usedDirectMemory
```
public static long usedDirectMemory()
```
    Returns the accumulated amount of memory in bytes used by direct ByteBuffers or 0 if the value cannot be determined.
    (i.e. ever allocated via ByteBuffer.allocateDirect())
    
    Returns:
    
    the accumulated amount of memory in bytes used by direct ByteBuffers or 0 if the value cannot be determined
  - usedNativeMemory
```
public static long usedNativeMemory()
```
    Returns the accumulated amount of memory used in bytes by UnsafeMemory.allocate().
    
    Returns:
    
    the accumulated amount of memory used in bytes by UnsafeMemory.allocate()
  - maxDirectMemory
```
public static long maxDirectMemory()
```
    Returns the maximum direct memory in bytes that can ever be allocated or 0 if the value cannot be determined. (i.e. ever allocated via ByteBuffer.allocateDirect())
    
    Returns:
    
    the maximum direct memory in bytes that can ever be allocated or 0 if the value cannot be determined
  - is64bit
```
public static boolean is64bit()
```
    Returns if the JVM runs in 64 bit mode.
    
    Returns:
    
    if the JVM runs in 64 bit mode
  - resetExceptionHandlers
```
public static void resetExceptionHandlers()
```
  - disableDebugHandler
```
public static void disableDebugHandler()
```
  - recordExceptions
```
@NotNull
public static @NotNull Map<ExceptionKey,Integer> recordExceptions()
```
  - recordExceptions
```
@NotNull
public static @NotNull Map<ExceptionKey,Integer> recordExceptions(boolean debug)
```
  - recordExceptions
```
@NotNull
public static @NotNull Map<ExceptionKey,Integer> recordExceptions(boolean debug,
                                                                           boolean exceptionsOnly)
```
  - recordExceptions
```
@NotNull
public static @NotNull Map<ExceptionKey,Integer> recordExceptions(boolean debug,
                                                                           boolean exceptionsOnly,
                                                                           boolean logToSlf4j)
```
  - hasException
```
public static boolean hasException(@NotNull
                                   @NotNull Map<ExceptionKey,Integer> exceptions)
```
  - setExceptionsHandlers
```
@Deprecated
public static void setExceptionsHandlers(@Nullable
                                                     @Nullable ExceptionHandler fatal,
                                                     @Nullable
                                                     @Nullable ExceptionHandler warn,
                                                     @Nullable
                                                     @Nullable ExceptionHandler debug)
```
    Deprecated.
  - setExceptionHandlers
```
public static void setExceptionHandlers(@Nullable
                                        @Nullable ExceptionHandler fatal,
                                        @Nullable
                                        @Nullable ExceptionHandler warn,
                                        @Nullable
                                        @Nullable ExceptionHandler debug)
```
  - setExceptionHandlers
```
public static void setExceptionHandlers(@Nullable
                                        @Nullable ExceptionHandler fatal,
                                        @Nullable
                                        @Nullable ExceptionHandler warn,
                                        @Nullable
                                        @Nullable ExceptionHandler debug,
                                        @Nullable
                                        @Nullable ExceptionHandler perf)
```
  - setExceptionHandlers
```
public static void setExceptionHandlers(@Nullable
                                        @Nullable ExceptionHandler fatal,
                                        @Nullable
                                        @Nullable ExceptionHandler error,
                                        @Nullable
                                        @Nullable ExceptionHandler warn,
                                        @Nullable
                                        @Nullable ExceptionHandler debug,
                                        @Nullable
                                        @Nullable ExceptionHandler perf)
```
  - setThreadLocalExceptionHandlers
```
public static void setThreadLocalExceptionHandlers(@Nullable
                                                   @Nullable ExceptionHandler fatal,
                                                   @Nullable
                                                   @Nullable ExceptionHandler warn,
                                                   @Nullable
                                                   @Nullable ExceptionHandler debug)
```
  - setThreadLocalExceptionHandlers
```
public static void setThreadLocalExceptionHandlers(@Nullable
                                                   @Nullable ExceptionHandler fatal,
                                                   @Nullable
                                                   @Nullable ExceptionHandler warn,
                                                   @Nullable
                                                   @Nullable ExceptionHandler debug,
                                                   @Nullable
                                                   @Nullable ExceptionHandler perf)
```
  - setThreadLocalExceptionHandlers
```
public static void setThreadLocalExceptionHandlers(@Nullable
                                                   @Nullable ExceptionHandler fatal,
                                                   @Nullable
                                                   @Nullable ExceptionHandler error,
                                                   @Nullable
                                                   @Nullable ExceptionHandler warn,
                                                   @Nullable
                                                   @Nullable ExceptionHandler debug,
                                                   @Nullable
                                                   @Nullable ExceptionHandler perf)
```
  - fatal
```
@Deprecated
 @NotNull
public static @NotNull ExceptionHandler fatal()
```
    Deprecated. use error()
  - error
```
@NotNull
public static @NotNull ExceptionHandler error()
```
  - warn
```
@NotNull
public static @NotNull ExceptionHandler warn()
```
  - startup
```
@NotNull
public static @NotNull ExceptionHandler startup()
```
  - perf
```
@NotNull
public static @NotNull ExceptionHandler perf()
```
  - debug
```
@NotNull
public static @NotNull ExceptionHandler debug()
```
  - dumpException
```
public static void dumpException(@NotNull
                                 @NotNull Map<ExceptionKey,Integer> exceptions)
```
  - isDebugEnabled
```
public static boolean isDebugEnabled(Class<?> aClass)
```
  - signalHandler
```
public static void signalHandler(sun.misc.SignalHandler signalHandler)
```
    Adds the provided signalHandler to an internal chain of handlers that will be invoked upon detecting system signals (e.g. HUP, INT, TERM).
    Not all signals are available on all operating systems.
    
    Parameters:
    
    signalHandler - to call on a signal
  - safepoint
```
public static void safepoint()
```
    Inserts a low-cost Java safe-point in the code path.
  - optionalSafepoint
```
@Deprecated
public static void optionalSafepoint()
```
    Deprecated.
  - areOptionalSafepointsEnabled
```
public static boolean areOptionalSafepointsEnabled()
```
  - stackTraceEndsWith
```
public static boolean stackTraceEndsWith(String endsWith,
                                         int maxDepth)
```
    Returns if there is a class name that ends with the provided endsWith string when examining the current stack trace of depth at most up to the provided maxDepth.
    
    Parameters:
    
    endsWith - to test against the current stack trace
    
    maxDepth - to examine
    
    Returns:
    
    if there is a class name that ends with the provided endsWith string when examining the current stack trace of depth at most up to the provided maxDepth
  - isArm
```
public static boolean isArm()
```
    Returns if the JVM runs on a CPU using the ARM architecture.
    
    Returns:
    
    if the JVM runs on a CPU using the ARM architecture
  - classMetrics
```
@NotNull
public static @NotNull ClassMetrics classMetrics(Class<?> clazz)
                                                   throws IllegalArgumentException
```
    Acquires and returns the ClassMetrics for the provided clazz.
    
    Parameters:
    
    clazz - for which ClassMetrics shall be acquired
    
    Returns:
    
    the ClassMetrics for the provided clazz
    
    Throws:
    
    IllegalArgumentException - if no ClassMetrics can be acquired
    
    See Also:
    
    ClassMetrics
  - userHome
```
@NotNull
public static @NotNull String userHome()
```
    Returns the user's home directory (e.g. "/home/alice") or "." if the user's home director cannot be determined.
    
    Returns:
    
    the user's home directory (e.g. "/home/alice") or "." if the user's home director cannot be determined
  - dontChain
```
public static boolean dontChain(Class<?> tClass)
```
  - isResourceTracing
```
public static boolean isResourceTracing()
```
    Returns if certain chronicle resources (such as memory regions) are traced.
    Tracing resources incurs slightly less performance but provides a means of detecting proper release of resources.
    
    Returns:
    
    if certain chronicle resources (such as memory regions) are traced
  - getBoolean
```
public static boolean getBoolean(String systemPropertyKey)
```
    Returns if a System Property with the provided systemPropertyKey either exists, is set to "yes" or is set to "true".
    This provides a more permissive boolean System systemPropertyKey flag where -Dflag -Dflag=true -Dflag=yes are all accepted.
    
    Parameters:
    
    systemPropertyKey - name to lookup
    
    Returns:
    
    if a System Property with the provided systemPropertyKey either exists, is set to "yes" or is set to "true"
  - getBoolean
```
public static boolean getBoolean(String systemPropertyKey,
                                 boolean defaultValue)
```
    Returns if a System Property with the provided systemPropertyKey either exists, is set to "yes" or is set to "true" or, if it does not exist, returns the provided defaultValue.
    This provides a more permissive boolean System systemPropertyKey flag where -Dflag -Dflag=true -Dflag=yes are all accepted.
    
    Parameters:
    
    systemPropertyKey - name to lookup
    
    defaultValue - value to be used if unknown
    
    Returns:
    
    if a System Property with the provided systemPropertyKey either exists, is set to "yes" or is set to "true" or, if it does not exist, returns the provided defaultValue.
  - parseSize
```
public static long parseSize(@NotNull
                             @NotNull String value)
                      throws IllegalArgumentException
```
    Parse a string as a decimal memory size with an optional scale. K/k = * 2¹⁰, M/m = 2²⁰, G/g = 2¹⁰, T/t = 2⁴⁰
    trailing B/b/iB/ib are ignored.
    
    100 100 bytes
    
    100b 100 bytes
    
    0.5kb 512 bytes
    
    0.125MB 128 KiB
    
    2M 2 MiB
    
    0.75GiB 768 MiB
    
    0.001TiB 1.024 GiB
    
    Parameters:
    
    value - size to parse
    
    Returns:
    
    the size
    
    Throws:
    
    IllegalArgumentException - if the string could be parsed
  - getSize
```
public static long getSize(String property,
                           long defaultValue)
```
    Uses Jvm.parseSize to parse a system property or returns defaultValue if not present, empty or unparseable.
    
    Parameters:
    
    property - to look up
    
    defaultValue - to use otherwise
    
    Returns:
    
    the size in bytes as a long
  - address
```
public static long address(@NotNull
                           @NotNull ByteBuffer byteBuffer)
```
    Returns the native address of the provided byteBuffer.
    Use with caution!. Native address should always be carefully guarded to prevent unspecified results or even JVM crashes.
    
    Parameters:
    
    byteBuffer - from which to extract the native address
    
    Returns:
    
    the native address of the provided byteBuffer
  - arrayByteBaseOffset
```
public static int arrayByteBaseOffset()
```
    Returns the array byte base offset used by this JVM.
    The value is the number of bytes that precedes the actual memory layout of a byte[] array in a java array object.
    Use with caution!. Native address should always be carefully guarded to prevent unspecified results or even JVM crashes.
    
    Returns:
    
    the array byte base offset used by this JVM
  - doNotCloseOnInterrupt
```
public static void doNotCloseOnInterrupt(Class<?> clazz,
                                         FileChannel fc)
```
    Employs a best-effort of preventing the provided fc from being automatically closed whenever the current thread gets interrupted.
    If the effort failed, the provided clazz is used for logging purposes.
    
    Parameters:
    
    clazz - to use for logging should the effort fail.
    
    fc - to prevent from automatically closing upon interrupt.
  - addToClassPath
```
public static void addToClassPath(@NotNull
                                  @NotNull Class<?> clazz)
```
    Ensures that all the jars and other resources are added to the class path of the classloader associated by the provided clazz.
    
    Parameters:
    
    clazz - to use as a template.
  - getDouble
```
public static double getDouble(String systemPropertyKey,
                               double defaultValue)
```
    Returns the System Property associated with the provided systemPropertyKey parsed as a double or, if no such parsable System Property exists, returns the provided defaultValue.
    
    Parameters:
    
    systemPropertyKey - to lookup in the System Properties
    
    defaultValue - to be used if no parsable key association exists
    
    Returns:
    
    the System Property associated with the provided systemPropertyKey parsed as a double or, if no such parsable System Property exists, returns the provided defaultValue
  - isProcessAlive
```
public static boolean isProcessAlive(long pid)
```
    Returns if a process with the provided pid process id is alive.
    
    Parameters:
    
    pid - the process id (pid) of the process to check
    
    Returns:
    
    if a process with the provided pid process id is alive
  - isAzulZing
```
public static boolean isAzulZing()
```
  - objectHeaderSize
```
public static int objectHeaderSize()
```

100	100 bytes
100b	100 bytes
0.5kb	512 bytes
0.125MB	128 KiB
2M	2 MiB
0.75GiB	768 MiB
0.001TiB	1.024 GiB

Enum Jvm

Field Summary

Method Summary

Methods inherited from class java.lang.Enum

Methods inherited from class java.lang.Object

Field Detail

JAVA_CLASS_PATH

SYSTEM_PROPERTIES

Method Detail

values

valueOf

init

compileThreshold

majorVersion

isJava9Plus

isJava12Plus

isJava14Plus

getProcessId

rethrow

trimStackTrace

trimLast

isDebug

isFlightRecorder

isCodeCoverage

pause

nanoPause

busyWaitMicros

busyWaitUntil

getField

getFieldOrNull

getMethod

setAccessible

getValue

lockWithStack

usedDirectMemory

usedNativeMemory

maxDirectMemory

is64bit

resetExceptionHandlers

disableDebugHandler

recordExceptions

recordExceptions

recordExceptions

recordExceptions

hasException

setExceptionsHandlers

setExceptionHandlers

setExceptionHandlers

setExceptionHandlers

setThreadLocalExceptionHandlers

setThreadLocalExceptionHandlers

setThreadLocalExceptionHandlers

fatal

error

warn

startup

perf

debug

dumpException

isDebugEnabled

signalHandler

safepoint

optionalSafepoint

areOptionalSafepointsEnabled

stackTraceEndsWith

isArm

classMetrics

userHome

dontChain

isResourceTracing

getBoolean

getBoolean

parseSize

getSize

address

arrayByteBaseOffset

doNotCloseOnInterrupt

addToClassPath

getDouble

isProcessAlive