publicstaticByteBufferallocateDirect(int capacity){returnnewDirectByteBuffer(capacity);}DirectByteBuffer(int cap){...protectedstaticfinal Unsafe unsafe=Bits.unsafe();unsafe.allocateMemory(size);...}publicfinal
kclass pointer:32bits architectures上,kclass pointer占32bits,64bits architectures上,kclass pointer占64bits,但也可能是32bits,原话是这样"theklass pointerhas word size on32 bitarchitectures. On64 bitarchitectures the klass pointer either has word size, but can also have4 byteif the heap addresses ...
private static final int COUNT_BITS = Integer.SIZE - 3; // =29 private static final int CAPACITY = (1 << COUNT_BITS) - 1; // =000 11111... // runState is stored in the high-order bits private static final int RUNNING = -1 << COUNT_BITS; // 111 00000... private static fin...
Si vous utilisez des navigateurs 32 bits et 64 bits sans distinction, vous devez installer Java 32 bits et Java 64 bits pour disposer du plug-in Java dans tous vos navigateurs. » FAQ relative à Java 64 bits pour Windows Mac OS X FAQ MacmacOS x64 (10.7.3 et versions supérieures...
Klass Word:存储一个地址,长度取决于系统位数,32位和64位,该地址指向方法区中类的元数据信息。 常见的虚拟机分为32位和64位,则其对象头也会不同: 在32位系统中,Mark Word = 4 bytes = 32 bits,对象头 = 8 bytes = 64 bits; 在64位系统中,Mark Word = 8 bytes = 64 bits ,对象头 = 16 bytes ...
(位于:src/share/vm/interpreter/interpreterRuntime.cpp) 的 InterpreterRuntime::monitorenter函 数。具体代码可参见HotSpot源码。 IRT_ENTRY_NO_ASYNC(void, InterpreterRuntime::monitorenter(JavaThread* thread, BasicObjectLock* elem)) #ifdef ASSERT
不是必然存在的,也没有特别的含义,它仅仅起着占位符的作用。由于HotSpot VM的自动内存管理系统要求对象起始地址必须是8字节的整数倍,换句话说,就是对象的大小必须是8字节的整数倍。而对象头部分正好是8字节的倍数(1倍或者2倍),因此,当对象实例数据部分没有对齐时,就需要通过对齐填充来补全。
"C:\Program Files" se ajustará a "C:\Program Files (x86)" para los entornos Java de 32 bits.Se creará una unión en C:\Program Files\Java\latest\jre-1.8. Apuntará al JRE más reciente de la familia 8.JDK-8329700 (no público) Actualización de JDK Oracle recomienda que se ...
Tiered compilation is the default mode for the server VM. Both 32 and 64 bit modes are supported, as well as compressed oops (see the next section). Use the-XX:-TieredCompilationflag with thejavacommand to disable tiered compilation.
privatestaticlonginitialSeed() {// 尝试获取 JVM 的启动参数 String sec = VM.getSavedProperty("java.util.secureRandomSeed");// 如果启动参数设置的值为 true，则参数一个随机 8 位的种子if (Boolean.parseBoolean(sec)) {byte[] seedBytes = java.security.SecureRandom.getSeed(8);long s = (long)...