java.lang.Object
- java.lang.Enum<JvmInformation>
- - net.sf.ehcache.pool.sizeof.JvmInformation

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<JvmInformation>
```
public enum JvmInformation
extends java.lang.Enum<JvmInformation>
```
Detects and represents JVM-specific properties that relate to the memory data model for java objects that are useful for size of calculations.

Author:

jhouse, Chris Dennis

Enum Constant Summary

Enum Constants
Enum Constant	Description
`HOTSPOT_32_BIT`	Represents HotSpot 32-bit
`HOTSPOT_32_BIT_WITH_CONCURRENT_MARK_AND_SWEEP`	Represents 32-Bit HotSpot JVM with Concurrent Mark-and-Sweep GC
`HOTSPOT_64_BIT`	Represents 64-Bit HotSpot JVM
`HOTSPOT_64_BIT_WITH_COMPRESSED_OOPS`	Represents 64-Bit HotSpot JVM with Compressed OOPs
`HOTSPOT_64_BIT_WITH_COMPRESSED_OOPS_AND_CONCURRENT_MARK_AND_SWEEP`	Represents 64-Bit HotSpot JVM with Compressed OOPs and Concurrent Mark-and-Sweep GC
`HOTSPOT_64_BIT_WITH_CONCURRENT_MARK_AND_SWEEP`	Represents 64-Bit HotSpot JVM with Concurrent Mark-and-Sweep GC
`IBM_32_BIT`	Represents IBM 32-bit
`IBM_64_BIT`	Represents 64-Bit IBM JVM (with no reference compression)
`IBM_64_BIT_WITH_COMPRESSED_REFS`	Represents 64-Bit IBM JVM (with reference compression)
`OPENJDK_32_BIT`	Represents OpenJDK 32-bit
`OPENJDK_32_BIT_WITH_CONCURRENT_MARK_AND_SWEEP`	Represents 32-Bit OpenJDK JVM with Concurrent Mark-and-Sweep GC
`OPENJDK_64_BIT`	Represents 64-Bit OpenJDK JVM
`OPENJDK_64_BIT_WITH_COMPRESSED_OOPS`	Represents 64-Bit OpenJDK JVM with Compressed OOPs
`OPENJDK_64_BIT_WITH_COMPRESSED_OOPS_AND_CONCURRENT_MARK_AND_SWEEP`	Represents 64-Bit OpenJDK JVM with Compressed OOPs and Concurrent Mark-and-Sweep GC
`OPENJDK_64_BIT_WITH_CONCURRENT_MARK_AND_SWEEP`	Represents 64-Bit OpenJDK JVM with Concurrent Mark-and-Sweep GC
`UNKNOWN_32_BIT`	Represents Generic 32-bit
`UNKNOWN_64_BIT`	Represents 64-Bit Generic JVM

Field Summary

Fields
Modifier and Type Field Description

static JvmInformation CURRENT_JVM_INFORMATION
The JvmInformation instance representing the current JVM

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`int`	`getAgentSizeOfAdjustment()`	The size of the jvm-specific agent result adjustment in bytes.
`int`	`getFieldOffsetAdjustment()`	The size of the jvm-specific field offset adjustment in bytes.
`int`	`getJavaPointerSize()`	Size of a java pointer in bytes on this runtime (that differs when compressedOops are being used)
`abstract java.lang.String`	`getJvmDescription()`	A human-readable description of the JVM and its relevant enabled options.Os
`int`	`getMinimumObjectSize()`	Minimal size an object will occupy on the heap in bytes.
`int`	`getObjectAlignment()`	Object alignment / padding in bytes
`int`	`getObjectHeaderSize()`	The size of an object header in bytes.
`int`	`getPointerSize()`	Size of a pointer in bytes on this runtime
`static boolean`	`isHotspot()`	Returns true if VM vendor is Hotspot
`static boolean`	`isIBM()`	Returns true if VM vendor is IBM
`static boolean`	`isOpenJDK()`	Returns true if VM vendor is OpenJDK
`static boolean`	`isOSX()`	Return true if the VM's vendor is Apple
`boolean`	`supportsAgentSizeOf()`	Whether the jvm can support AgentSizeOf implementation.
`boolean`	`supportsReflectionSizeOf()`	Whether the jvm can support ReflectionSizeOf implementation.
`boolean`	`supportsUnsafeSizeOf()`	Whether the jvm can support UnsafeSizeOf implementation.
`static JvmInformation`	`valueOf(java.lang.String name)`	Returns the enum constant of this type with the specified name.
`static JvmInformation[]`	`values()`	Returns an array containing the constants of this enum type, in the order they are declared.

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

- Enum Constant Detail
  - UNKNOWN_32_BIT
```
public static final JvmInformation UNKNOWN_32_BIT
```
    Represents Generic 32-bit
  - UNKNOWN_64_BIT
```
public static final JvmInformation UNKNOWN_64_BIT
```
    Represents 64-Bit Generic JVM
  - HOTSPOT_32_BIT
```
public static final JvmInformation HOTSPOT_32_BIT
```
    Represents HotSpot 32-bit
  - HOTSPOT_32_BIT_WITH_CONCURRENT_MARK_AND_SWEEP
```
public static final JvmInformation HOTSPOT_32_BIT_WITH_CONCURRENT_MARK_AND_SWEEP
```
    Represents 32-Bit HotSpot JVM with Concurrent Mark-and-Sweep GC
  - HOTSPOT_64_BIT
```
public static final JvmInformation HOTSPOT_64_BIT
```
    Represents 64-Bit HotSpot JVM
  - HOTSPOT_64_BIT_WITH_CONCURRENT_MARK_AND_SWEEP
```
public static final JvmInformation HOTSPOT_64_BIT_WITH_CONCURRENT_MARK_AND_SWEEP
```
    Represents 64-Bit HotSpot JVM with Concurrent Mark-and-Sweep GC
  - HOTSPOT_64_BIT_WITH_COMPRESSED_OOPS
```
public static final JvmInformation HOTSPOT_64_BIT_WITH_COMPRESSED_OOPS
```
    Represents 64-Bit HotSpot JVM with Compressed OOPs
  - HOTSPOT_64_BIT_WITH_COMPRESSED_OOPS_AND_CONCURRENT_MARK_AND_SWEEP
```
public static final JvmInformation HOTSPOT_64_BIT_WITH_COMPRESSED_OOPS_AND_CONCURRENT_MARK_AND_SWEEP
```
    Represents 64-Bit HotSpot JVM with Compressed OOPs and Concurrent Mark-and-Sweep GC
  - OPENJDK_32_BIT
```
public static final JvmInformation OPENJDK_32_BIT
```
    Represents OpenJDK 32-bit
  - OPENJDK_32_BIT_WITH_CONCURRENT_MARK_AND_SWEEP
```
public static final JvmInformation OPENJDK_32_BIT_WITH_CONCURRENT_MARK_AND_SWEEP
```
    Represents 32-Bit OpenJDK JVM with Concurrent Mark-and-Sweep GC
  - OPENJDK_64_BIT
```
public static final JvmInformation OPENJDK_64_BIT
```
    Represents 64-Bit OpenJDK JVM
  - OPENJDK_64_BIT_WITH_CONCURRENT_MARK_AND_SWEEP
```
public static final JvmInformation OPENJDK_64_BIT_WITH_CONCURRENT_MARK_AND_SWEEP
```
    Represents 64-Bit OpenJDK JVM with Concurrent Mark-and-Sweep GC
  - OPENJDK_64_BIT_WITH_COMPRESSED_OOPS
```
public static final JvmInformation OPENJDK_64_BIT_WITH_COMPRESSED_OOPS
```
    Represents 64-Bit OpenJDK JVM with Compressed OOPs
  - OPENJDK_64_BIT_WITH_COMPRESSED_OOPS_AND_CONCURRENT_MARK_AND_SWEEP
```
public static final JvmInformation OPENJDK_64_BIT_WITH_COMPRESSED_OOPS_AND_CONCURRENT_MARK_AND_SWEEP
```
    Represents 64-Bit OpenJDK JVM with Compressed OOPs and Concurrent Mark-and-Sweep GC
  - IBM_32_BIT
```
public static final JvmInformation IBM_32_BIT
```
    Represents IBM 32-bit
  - IBM_64_BIT
```
public static final JvmInformation IBM_64_BIT
```
    Represents 64-Bit IBM JVM (with no reference compression)
  - IBM_64_BIT_WITH_COMPRESSED_REFS
```
public static final JvmInformation IBM_64_BIT_WITH_COMPRESSED_REFS
```
    Represents 64-Bit IBM JVM (with reference compression)
- Field Detail
  - CURRENT_JVM_INFORMATION
```
public static final JvmInformation CURRENT_JVM_INFORMATION
```
    The JvmInformation instance representing the current JVM
- Method Detail
  - values
```
public static JvmInformation[] 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 (JvmInformation c : JvmInformation.values()) System.out.println(c);
    Returns:
    
    an array containing the constants of this enum type, in the order they are declared
  - valueOf
```
public static JvmInformation valueOf(java.lang.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:
    
    java.lang.IllegalArgumentException - if this enum type has no constant with the specified name
    
    java.lang.NullPointerException - if the argument is null
  - getPointerSize
```
public int getPointerSize()
```
    Size of a pointer in bytes on this runtime
  - getJavaPointerSize
```
public int getJavaPointerSize()
```
    Size of a java pointer in bytes on this runtime (that differs when compressedOops are being used)
  - getMinimumObjectSize
```
public int getMinimumObjectSize()
```
    Minimal size an object will occupy on the heap in bytes.
  - getObjectAlignment
```
public int getObjectAlignment()
```
    Object alignment / padding in bytes
  - getObjectHeaderSize
```
public int getObjectHeaderSize()
```
    The size of an object header in bytes.
  - getFieldOffsetAdjustment
```
public int getFieldOffsetAdjustment()
```
    The size of the jvm-specific field offset adjustment in bytes.
  - getAgentSizeOfAdjustment
```
public int getAgentSizeOfAdjustment()
```
    The size of the jvm-specific agent result adjustment in bytes.
  - supportsAgentSizeOf
```
public boolean supportsAgentSizeOf()
```
    Whether the jvm can support AgentSizeOf implementation.
  - supportsUnsafeSizeOf
```
public boolean supportsUnsafeSizeOf()
```
    Whether the jvm can support UnsafeSizeOf implementation.
  - supportsReflectionSizeOf
```
public boolean supportsReflectionSizeOf()
```
    Whether the jvm can support ReflectionSizeOf implementation.
  - getJvmDescription
```
public abstract java.lang.String getJvmDescription()
```
    A human-readable description of the JVM and its relevant enabled options.Os
  - isOSX
```
public static boolean isOSX()
```
    Return true if the VM's vendor is Apple
    
    Returns:
    
    true, if OS X
  - isHotspot
```
public static boolean isHotspot()
```
    Returns true if VM vendor is Hotspot
    
    Returns:
    
    true, if Hotspot
  - isOpenJDK
```
public static boolean isOpenJDK()
```
    Returns true if VM vendor is OpenJDK
    
    Returns:
    
    true, if OpenJDK
  - isIBM
```
public static boolean isIBM()
```
    Returns true if VM vendor is IBM
    
    Returns:
    
    true, if IBM

Enum JvmInformation

Enum Constant Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Enum

Methods inherited from class java.lang.Object

Enum Constant Detail

UNKNOWN_32_BIT

UNKNOWN_64_BIT

HOTSPOT_32_BIT

HOTSPOT_32_BIT_WITH_CONCURRENT_MARK_AND_SWEEP

HOTSPOT_64_BIT

HOTSPOT_64_BIT_WITH_CONCURRENT_MARK_AND_SWEEP

HOTSPOT_64_BIT_WITH_COMPRESSED_OOPS

HOTSPOT_64_BIT_WITH_COMPRESSED_OOPS_AND_CONCURRENT_MARK_AND_SWEEP

OPENJDK_32_BIT

OPENJDK_32_BIT_WITH_CONCURRENT_MARK_AND_SWEEP

OPENJDK_64_BIT

OPENJDK_64_BIT_WITH_CONCURRENT_MARK_AND_SWEEP

OPENJDK_64_BIT_WITH_COMPRESSED_OOPS

OPENJDK_64_BIT_WITH_COMPRESSED_OOPS_AND_CONCURRENT_MARK_AND_SWEEP

IBM_32_BIT

IBM_64_BIT

IBM_64_BIT_WITH_COMPRESSED_REFS

Field Detail

CURRENT_JVM_INFORMATION

Method Detail

values

valueOf

getPointerSize

getJavaPointerSize

getMinimumObjectSize

getObjectAlignment

getObjectHeaderSize

getFieldOffsetAdjustment

getAgentSizeOfAdjustment

supportsAgentSizeOf

supportsUnsafeSizeOf

supportsReflectionSizeOf

getJvmDescription

isOSX

isHotspot

isOpenJDK

isIBM