Jvm (OpenHFT/Chronicle-Core 2.19.8 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.

Method Summary

All Methods Static Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`static boolean`	`areOptionalSafepointsEnabled()`
`static void`	`busyWaitMicros(long micros)` This method is designed to be used when the time to be waited is very small, typically under a millisecond.
`static void`	`busyWaitUntil(long waitUntil)` This method is designed to be used when the time to be waited is very small, typically under a millisecond.
`static ClassMetrics`	`classMetrics(Class c)`
`static int`	`compileThreshold()`
`static @NotNull ExceptionHandler`	`debug()`
`static void`	`disableDebugHandler()`
`static boolean`	`dontChain(Class tClass)`
`static void`	`dumpException(@NotNull Map<ExceptionKey,Integer> exceptions)`
`static @NotNull ExceptionHandler`	`fatal()`
`static Field`	`getField(@NotNull Class clazz, @NotNull String name)` Get the Field for a class by name.
`static Method`	`getMethod(@NotNull Class clazz, @NotNull String name, Class... args)`
`static int`	`getProcessId()`
`static <V> V`	`getValue(@NotNull Object obj, @NotNull String name)`
`static boolean`	`hasException(@NotNull Map<ExceptionKey,Integer> exceptions)`
`static void`	`init()`
`static boolean`	`is64bit()`
`static boolean`	`isArm()`
`static boolean`	`isDebug()`
`static boolean`	`isDebugEnabled(Class aClass)`
`static boolean`	`isFlightRecorder()`
`static boolean`	`isJava12Plus()`
`static boolean`	`isJava14Plus()`
`static boolean`	`isJava9Plus()`
`static String`	`lockWithStack(@NotNull ReentrantLock lock)` Log the stack trace of the thread holding a lock.
`static int`	`majorVersion()`
`static long`	`maxDirectMemory()`
`static void`	`nanoPause()` Pause in a busy loop for a very short time.
`static void`	`optionalSafepoint()`
`static void`	`pause(long millis)` Silently pause for milli seconds.
`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 a CheckedException as an unchecked one.
`static void`	`safepoint()`
`static void`	`setAccessible(AccessibleObject h)`
`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`	`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`	`signalHandler(sun.misc.SignalHandler signalHandler)` Helper method for setting the default signals.
`static boolean`	`stackTraceEndsWith(String endsWith, int n)`
`static int`	`trimLast(int first, @NotNull StackTraceElement[] stes)`
`static void`	`trimStackTrace(@NotNull StringBuilder sb, StackTraceElement... stes)` Append the StackTraceElements to the StringBuilder trimming some internal methods.
`static long`	`usedDirectMemory()`
`static long`	`usedNativeMemory()`
`static String`	`userHome()`
`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

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()
```

majorVersion
```
public static int majorVersion()
```

isJava9Plus
```
public static boolean isJava9Plus()
```

isJava12Plus
```
public static boolean isJava12Plus()
```

isJava14Plus
```
public static boolean isJava14Plus()
```

getProcessId
```
public static int getProcessId()
```

rethrow
```
@NotNull
public static <T extends Throwable> @NotNull RuntimeException rethrow(Throwable throwable)
                                                                        throws T extends Throwable
```
Cast a CheckedException as an unchecked one.

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 sb,
                                  @NotNull
                                  StackTraceElement... stes)

Append the StackTraceElements to the StringBuilder trimming some internal methods.

Parameters:: sb - to append to; stes - stack trace elements

trimLast

public static int trimLast(int first,
                           @NotNull
                           @NotNull StackTraceElement[] stes)

isDebug
```
public static boolean isDebug()
```
Returns:

is the JVM in debug mode.

isFlightRecorder
```
public static boolean isFlightRecorder()
```
Returns:

is the JVM in flight recorder mode.

pause
```
public static void pause(long millis)
```
Silently pause for milli seconds.

Parameters:

millis - to sleep for.

nanoPause
```
public static void nanoPause()
```
Pause in a busy loop for a very short time.

busyWaitMicros
```
public static void busyWaitMicros(long micros)
```
This method is designed to be used when the time to be waited is very small, typically under a millisecond.

Parameters:

micros - Time in micros

busyWaitUntil
```
public static void busyWaitUntil(long waitUntil)
```
This method is designed to be used when the time to be waited is very small, typically under a millisecond.

Parameters:

waitUntil - nanosecond precision counter value to await.

getField

public static Field getField(@NotNull
                             @NotNull Class clazz,
                             @NotNull
                             @NotNull String name)

Get the Field for a class by name.

Parameters:: clazz - to get the field for; name - of the field
Returns:: the Field.

getMethod

public static Method getMethod(@NotNull
                               @NotNull Class clazz,
                               @NotNull
                               @NotNull String name,
                               Class... args)

setAccessible

public static void setAccessible(AccessibleObject h)

getValue

public static <V> V getValue(@NotNull
                             @NotNull Object obj,
                             @NotNull
                             @NotNull String name)

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 size of memory used by direct ByteBuffers i.e. ByteBuffer.allocateDirect()

usedNativeMemory
```
public static long usedNativeMemory()
```
Returns:

The size of memory used by UnsafeMemory.allocate()

maxDirectMemory
```
public static long maxDirectMemory()
```

is64bit
```
public static boolean is64bit()
```

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)

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)

fatal

@NotNull
public static @NotNull ExceptionHandler fatal()

warn

@NotNull
public static @NotNull ExceptionHandler warn()

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)
```
Helper method for setting the default signals. Every signal handler you register with this method will be called.

Parameters:

signalHandler - to call on a signal

safepoint
```
public static void safepoint()
```

optionalSafepoint

public static void optionalSafepoint()

areOptionalSafepointsEnabled

public static boolean areOptionalSafepointsEnabled()

stackTraceEndsWith

public static boolean stackTraceEndsWith(String endsWith,
                                         int n)

isArm
```
public static boolean isArm()
```

classMetrics

public static ClassMetrics classMetrics(Class c)
                                 throws IllegalArgumentException

Throws:: IllegalArgumentException

userHome
```
public static String userHome()
```

dontChain

public static boolean dontChain(Class tClass)

Enum Jvm

Method Summary

Methods inherited from class java.lang.Enum

Methods inherited from class java.lang.Object

Method Detail

values

valueOf

init

compileThreshold

majorVersion

isJava9Plus

isJava12Plus

isJava14Plus

getProcessId

rethrow

trimStackTrace

trimLast

isDebug

isFlightRecorder

pause

nanoPause

busyWaitMicros

busyWaitUntil

getField

getMethod

setAccessible

getValue

lockWithStack

usedDirectMemory

usedNativeMemory

maxDirectMemory

is64bit

resetExceptionHandlers

disableDebugHandler

recordExceptions

recordExceptions

recordExceptions

recordExceptions

hasException

setExceptionsHandlers

setExceptionHandlers

setExceptionHandlers

setThreadLocalExceptionHandlers

setThreadLocalExceptionHandlers

fatal

warn

perf

debug

dumpException

isDebugEnabled

signalHandler

safepoint

optionalSafepoint

areOptionalSafepointsEnabled

stackTraceEndsWith

isArm

classMetrics

userHome

dontChain