Java Runtime.getRuntime（）。freeMemory（）问题

我搜索并看到了一些线程，但没有一个解决我遇到的具体问题。

我试图使用Runtime.getRuntime().freeMemory() ， Runtime.getRuntime().maxMemory()和Runtime.getRuntime().totalMemory() Runtime.getRuntime().maxMemory()来监视我的内存使用情况。

在一次运行中，它表示在声明一个数组之前有2245273792个空闲字节，但程序在内存耗尽并且在尝试声明一个1104674816字节的数组时崩溃：

  Free memory (bytes): 2245273792 Maximum memory (bytes): 6710886400 Total memory available to JVM (bytes): 5606211584 OpenJDK 64-Bit Server VM warning: INFO: os::commit_memory(0x0000000728280000, 1104674816, 0) failed; error='Cannot allocate memory' (errno=12) There is insufficient memory for the Java Runtime Environment to continue. Native memory allocation (malloc) failed to allocate 1104674816 bytes for committing reserved memory. An error report file with more information is saved as: 

编辑：当分配不到一半的免费金额时，它怎么可能耗尽内存？ 耗尽内存对于这个程序来说非常糟糕; 有没有办法可以保证我的分配不多于可用的？ 调用System.gc（）会首先使可用/可用内存量更可靠吗？ 如果程序即将耗尽内存而不是让它崩溃，我可以抛出某种exception吗？

它崩溃的命令是： float[][] A = new float[NUM_SEQ_TOTAL_P1][NUM_SEQ_TOTAL_P2]; NUM_SEQ_TOTAL_P1 = 16009，NUM_SEQ_TOTAL_P2 = 16937。

编辑：根据评论者的要求粘贴错误日志的部分。

  There is insufficient memory for the Java Runtime Environment to continue. Native memory allocation (malloc) failed to allocate 1104674816 bytes for committing reserved memory. Possible reasons: The system is out of physical RAM or swap space In 32 bit mode, the process size limit was hit Possible solutions: Reduce memory load on the system Increase physical memory or swap space Check if swap backing store is full Use 64 bit Java on a 64 bit OS Decrease Java heap size (-Xmx/-Xms) Decrease number of Java threads Decrease Java thread stack sizes (-Xss) Set larger code cache with -XX:ReservedCodeCacheSize= This output file may be truncated or incomplete. Out of Memory Error (os_linux.cpp:2769), pid=14802, tid=140058464728832 JRE version: OpenJDK Runtime Environment (7.0_55-b14) (build 1.7.0_55-b14) Java VM: OpenJDK 64-Bit Server VM (24.51-b03 mixed mode linux-amd64 compressed oops) Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again --------------- THREAD --------------- Current thread (0x00007f61f0071000): VMThread [stack: 0x00007f61e6f9b000,0x00007f61e709c000] [id=14806] Stack: [0x00007f61e6f9b000,0x00007f61e709c000], sp=0x00007f61e709a470, free space=1021k Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code) V [libjvm.so+0x917b35] VMError::report_and_die()+0x175 V [libjvm.so+0x468144] report_vm_out_of_memory(char const*, int, unsigned long, char const*)+0x74 V [libjvm.so+0x79a81b] os::pd_commit_memory(char*, unsigned long, unsigned long, bool)+0x20b V [libjvm.so+0x7950df] os::commit_memory(char*, unsigned long, unsigned long, bool)+0x1f V [libjvm.so+0x8053cb] PSVirtualSpace::expand_by(unsigned long)+0x5b V [libjvm.so+0x7f519b] PSOldGen::expand_by(unsigned long) [clone .part.80]+0x1b V [libjvm.so+0x7f535b] PSOldGen::expand(unsigned long) [clone .part.81]+0xdb V [libjvm.so+0x7f6288] PSOldGen::resize(unsigned long)+0x188 V [libjvm.so+0x7fd2e3] PSParallelCompact::invoke_no_policy(bool)+0x9c3 V [libjvm.so+0x80350d] PSScavenge::invoke()+0x17d V [libjvm.so+0x7b9b33] ParallelScavengeHeap::failed_mem_allocate(unsigned long)+0x63 V [libjvm.so+0x919544] VM_ParallelGCFailedAllocation::doit()+0x84 V [libjvm.so+0x91d9e7] VM_Operation::evaluate()+0x47 V [libjvm.so+0x91c3b8] VMThread::evaluate_operation(VM_Operation*)+0x318 V [libjvm.so+0x91c85a] VMThread::loop()+0x25a V [libjvm.so+0x91cc62] VMThread::run()+0x72 V [libjvm.so+0x7974e2] java_start(Thread*)+0xf2 VM_Operation (0x00007f61f8b6b2e0): ParallelGCFailedAllocation, mode: safepoint, requested by thread 0x00007f61f000a000 --------------- PROCESS --------------- Java Threads: ( => current thread ) 0x00007f61f00a1800 JavaThread "Service Thread" daemon [_thread_blocked, id=14812, stack(0x00007f61e680c000,0x00007f61e690d000)] 0x00007f61f009f000 JavaThread "C2 CompilerThread1" daemon [_thread_blocked, id=14811, stack(0x00007f61e690d000,0x00007f61e6a0e000)] 0x00007f61f009c000 JavaThread "C2 CompilerThread0" daemon [_thread_blocked, id=14810, stack(0x00007f61e6a0e000,0x00007f61e6b0f000)] 0x00007f61f009a000 JavaThread "Signal Dispatcher" daemon [_thread_blocked, id=14809, stack(0x00007f61e6b0f000,0x00007f61e6c10000)] 0x00007f61f0077800 JavaThread "Finalizer" daemon [_thread_blocked, id=14808, stack(0x00007f61e6d99000,0x00007f61e6e9a000)] 0x00007f61f0075800 JavaThread "Reference Handler" daemon [_thread_blocked, id=14807, stack(0x00007f61e6e9a000,0x00007f61e6f9b000)] 0x00007f61f000a000 JavaThread "main" [_thread_blocked, id=14803, stack(0x00007f61f8a6c000,0x00007f61f8b6d000)] Other Threads: =>0x00007f61f0071000 VMThread [stack: 0x00007f61e6f9b000,0x00007f61e709c000] [id=14806] 0x00007f61f00ac000 WatcherThread [stack: 0x00007f61e670b000,0x00007f61e680c000] [id=14813] VM state:at safepoint (normal execution) VM Mutex/Monitor currently owned by a thread: ([mutex/lock_event]) [0x00007f61f0005ea0] ExpandHeap_lock - owner thread: 0x00007f61f0071000 [0x00007f61f0006520] Threads_lock - owner thread: 0x00007f61f0071000 [0x00007f61f0006a20] Heap_lock - owner thread: 0x00007f61f000a000 Heap PSYoungGen total 1638400K, used 205885K [0x000000076a000000, 0x0000000800000000, 0x0000000800000000) eden space 819200K, 0% used [0x000000076a000000,0x000000076a000000,0x000000079c000000) from space 819200K, 25% used [0x00000007ce000000,0x00000007da90f408,0x0000000800000000) to space 819200K, 0% used [0x000000079c000000,0x000000079c000000,0x00000007ce000000) ParOldGen total 3836416K, used 3836085K [0x000000063e000000, 0x0000000728280000, 0x000000076a000000) object space 3836416K, 99% used [0x000000063e000000,0x000000072822d6b8,0x0000000728280000) PSPermGen total 21504K, used 5549K [0x0000000633a00000, 0x0000000634f00000, 0x000000063e000000) object space 21504K, 25% used [0x0000000633a00000,0x0000000633f6b518,0x0000000634f00000) Card table byte_map: [0x00007f61f487d000,0x00007f61f56e1000] byte_map_base: 0x00007f61f16e0000 Polling page: 0x00007f61f8b7d000 Code Cache [0x00007f61ed000000, 0x00007f61ed270000, 0x00007f61f0000000) total_blobs=653 nmethods=373 adapters=234 free_code_cache=46884Kb largest_free_block=47925312 Compilation events (10 events): Event: 697.652 Thread 0x00007f61f009c000 394 playingAgent.tartanian7.PlayerAction::access$0 (5 bytes) Event: 697.652 Thread 0x00007f61f009c000 nmethod 394 0x00007f61ed1f0150 code [0x00007f61ed1f0280, 0x00007f61ed1f02d8] Event: 729.745 Thread 0x00007f61f009f000 395 java.nio.Buffer::remaining (10 bytes) Event: 729.745 Thread 0x00007f61f009f000 nmethod 395 0x00007f61ed1eff50 code [0x00007f61ed1f0080, 0x00007f61ed1f00d8] Event: 921.702 Thread 0x00007f61f009c000 396 playingAgent.riverSolver.DoylesGameRiver2::getRiverStrategy (451 bytes) Event: 921.710 Thread 0x00007f61f009f000 397 playingAgent.tartanian7.PokerUtils::countRoundDelimiters (42 bytes) Event: 921.714 Thread 0x00007f61f009f000 nmethod 397 0x00007f61ed1f8350 code [0x00007f61ed1f84a0, 0x00007f61ed1f86b8] Event: 921.720 Thread 0x00007f61f009f000 398 java.lang.String::startsWith (7 bytes) Event: 921.724 Thread 0x00007f61f009f000 nmethod 398 0x00007f61ed108010 code [0x00007f61ed108160, 0x00007f61ed108338] Event: 922.063 Thread 0x00007f61f009c000 nmethod 396 0x00007f61ed23db90 code [0x00007f61ed23e6e0, 0x00007f61ed244d78] GC Heap History (10 events): Event: 922.966 GC heap after Heap after GC invocations=137 (full 23): PSYoungGen total 1638400K, used 280234K [0x000000076a000000, 0x0000000800000000, 0x0000000800000000) eden space 819200K, 0% used [0x000000076a000000,0x000000076a000000,0x000000079c000000) from space 819200K, 34% used [0x00000007ce000000,0x00000007df1aa930,0x0000000800000000) to space 819200K, 0% used [0x000000079c000000,0x000000079c000000,0x00000007ce000000) ParOldGen total 3836416K, used 2558981K [0x000000063e000000, 0x0000000728280000, 0x000000076a000000) object space 3836416K, 66% used [0x000000063e000000,0x00000006da301608,0x0000000728280000) PSPermGen total 21504K, used 5548K [0x0000000633a00000, 0x0000000634f00000, 0x000000063e000000) object space 21504K, 25% used [0x0000000633a00000,0x0000000633f6b068,0x0000000634f00000) } Event: 941.023 GC heap before {Heap before GC invocations=138 (full 23): PSYoungGen total 1638400K, used 1099434K [0x000000076a000000, 0x0000000800000000, 0x0000000800000000) eden space 819200K, 100% used [0x000000076a000000,0x000000079c000000,0x000000079c000000) from space 819200K, 34% used [0x00000007ce000000,0x00000007df1aa930,0x0000000800000000) to space 819200K, 0% used [0x000000079c000000,0x000000079c000000,0x00000007ce000000) ParOldGen total 3836416K, used 2558981K [0x000000063e000000, 0x0000000728280000, 0x000000076a000000) object space 3836416K, 66% used [0x000000063e000000,0x00000006da301608,0x0000000728280000) PSPermGen total 21504K, used 5548K [0x0000000633a00000, 0x0000000634f00000, 0x000000063e000000) object space 21504K, 25% used [0x0000000633a00000,0x0000000633f6b258,0x0000000634f00000) Event: 941.125 GC heap after Heap after GC invocations=138 (full 23): PSYoungGen total 1638400K, used 463312K [0x000000076a000000, 0x0000000800000000, 0x0000000800000000) eden space 819200K, 0% used [0x000000076a000000,0x000000076a000000,0x000000079c000000) from space 819200K, 56% used [0x000000079c000000,0x00000007b8474158,0x00000007ce000000) to space 819200K, 0% used [0x00000007ce000000,0x00000007ce000000,0x0000000800000000) ParOldGen total 3836416K, used 2559185K [0x000000063e000000, 0x0000000728280000, 0x000000076a000000) object space 3836416K, 66% used [0x000000063e000000,0x00000006da334680,0x0000000728280000) PSPermGen total 21504K, used 5548K [0x0000000633a00000, 0x0000000634f00000, 0x000000063e000000) object space 21504K, 25% used [0x0000000633a00000,0x0000000633f6b258,0x0000000634f00000) } Event: 971.960 GC heap before {Heap before GC invocations=139 (full 23): PSYoungGen total 1638400K, used 1282512K [0x000000076a000000, 0x0000000800000000, 0x0000000800000000) eden space 819200K, 100% used [0x000000076a000000,0x000000079c000000,0x000000079c000000) from space 819200K, 56% used [0x000000079c000000,0x00000007b8474158,0x00000007ce000000) to space 819200K, 0% used [0x00000007ce000000,0x00000007ce000000,0x0000000800000000) ParOldGen total 3836416K, used 2559185K [0x000000063e000000, 0x0000000728280000, 0x000000076a000000) object space 3836416K, 66% used [0x000000063e000000,0x00000006da334680,0x0000000728280000) PSPermGen total 21504K, used 5549K [0x0000000633a00000, 0x0000000634f00000, 0x000000063e000000) object space 21504K, 25% used [0x0000000633a00000,0x0000000633f6b518,0x0000000634f00000) Event: 971.996 GC heap after Heap after GC invocations=139 (full 23): PSYoungGen total 1638400K, used 130974K [0x000000076a000000, 0x0000000800000000, 0x0000000800000000) eden space 819200K, 0% used [0x000000076a000000,0x000000076a000000,0x000000079c000000) from space 819200K, 15% used [0x00000007ce000000,0x00000007d5fe7b78,0x0000000800000000) to space 819200K, 0% used [0x000000079c000000,0x000000079c000000,0x00000007ce000000) ParOldGen total 3836416K, used 2559301K [0x000000063e000000, 0x0000000728280000, 0x000000076a000000) object space 3836416K, 66% used [0x000000063e000000,0x00000006da351710,0x0000000728280000) PSPermGen total 21504K, used 5549K [0x0000000633a00000, 0x0000000634f00000, 0x000000063e000000) object space 21504K, 25% used [0x0000000633a00000,0x0000000633f6b518,0x0000000634f00000) } Event: 972.098 GC heap before {Heap before GC invocations=140 (full 23): PSYoungGen total 1638400K, used 950174K [0x000000076a000000, 0x0000000800000000, 0x0000000800000000) eden space 819200K, 100% used [0x000000076a000000,0x000000079c000000,0x000000079c000000) from space 819200K, 15% used [0x00000007ce000000,0x00000007d5fe7b78,0x0000000800000000) to space 819200K, 0% used [0x000000079c000000,0x000000079c000000,0x00000007ce000000) ParOldGen total 3836416K, used 2559301K [0x000000063e000000, 0x0000000728280000, 0x000000076a000000) object space 3836416K, 66% used [0x000000063e000000,0x00000006da351710,0x0000000728280000) PSPermGen total 21504K, used 5549K [0x0000000633a00000, 0x0000000634f00000, 0x000000063e000000) object space 21504K, 25% used [0x0000000633a00000,0x0000000633f6b518,0x0000000634f00000) Event: 972.296 GC heap after Heap after GC invocations=140 (full 23): PSYoungGen total 1638400K, used 817538K [0x000000076a000000, 0x0000000800000000, 0x0000000800000000) eden space 819200K, 0% used [0x000000076a000000,0x000000076a000000,0x000000079c000000) from space 819200K, 99% used [0x000000079c000000,0x00000007cde60b18,0x00000007ce000000) to space 819200K, 0% used [0x00000007ce000000,0x00000007ce000000,0x0000000800000000) ParOldGen total 3836416K, used 2689286K [0x000000063e000000, 0x0000000728280000, 0x000000076a000000) object space 3836416K, 70% used [0x000000063e000000,0x00000006e2241b50,0x0000000728280000) PSPermGen total 21504K, used 5549K [0x0000000633a00000, 0x0000000634f00000, 0x000000063e000000) object space 21504K, 25% used [0x0000000633a00000,0x0000000633f6b518,0x0000000634f00000) } Event: 972.397 GC heap before {Heap before GC invocations=141 (full 23): PSYoungGen total 1638400K, used 1636738K [0x000000076a000000, 0x0000000800000000, 0x0000000800000000) eden space 819200K, 100% used [0x000000076a000000,0x000000079c000000,0x000000079c000000) from space 819200K, 99% used [0x000000079c000000,0x00000007cde60b18,0x00000007ce000000) to space 819200K, 0% used [0x00000007ce000000,0x00000007ce000000,0x0000000800000000) ParOldGen total 3836416K, used 2689286K [0x000000063e000000, 0x0000000728280000, 0x000000076a000000) object space 3836416K, 70% used [0x000000063e000000,0x00000006e2241b50,0x0000000728280000) PSPermGen total 21504K, used 5549K [0x0000000633a00000, 0x0000000634f00000, 0x000000063e000000) object space 21504K, 25% used [0x0000000633a00000,0x0000000633f6b518,0x0000000634f00000) Event: 972.791 GC heap after Heap after GC invocations=141 (full 23): PSYoungGen total 1638400K, used 817782K [0x000000076a000000, 0x0000000800000000, 0x0000000800000000) eden space 819200K, 0% used [0x000000076a000000,0x000000076a000000,0x000000079c000000) from space 819200K, 99% used [0x00000007ce000000,0x00000007ffe9d998,0x0000000800000000) to space 819200K, 0% used [0x000000079c000000,0x000000079c000000,0x00000007ce000000) ParOldGen total 3836416K, used 3506825K [0x000000063e000000, 0x0000000728280000, 0x000000076a000000) object space 3836416K, 91% used [0x000000063e000000,0x00000007140a2668,0x0000000728280000) PSPermGen total 21504K, used 5549K [0x0000000633a00000, 0x0000000634f00000, 0x000000063e000000) object space 21504K, 25% used [0x0000000633a00000,0x0000000633f6b518,0x0000000634f00000) } Event: 972.791 GC heap before {Heap before GC invocations=142 (full 24): PSYoungGen total 1638400K, used 817782K [0x000000076a000000, 0x0000000800000000, 0x0000000800000000) eden space 819200K, 0% used [0x000000076a000000,0x000000076a000000,0x000000079c000000) from space 819200K, 99% used [0x00000007ce000000,0x00000007ffe9d998,0x0000000800000000) to space 819200K, 0% used [0x000000079c000000,0x000000079c000000,0x00000007ce000000) ParOldGen total 3836416K, used 3506825K [0x000000063e000000, 0x0000000728280000, 0x000000076a000000) object space 3836416K, 91% used [0x000000063e000000,0x00000007140a2668,0x0000000728280000) PSPermGen total 21504K, used 5549K [0x0000000633a00000, 0x0000000634f00000, 0x000000063e000000) object space 21504K, 25% used [0x0000000633a00000,0x0000000633f6b518,0x0000000634f00000) Deoptimization events (10 events): Event: 388.757 Thread 0x00007f61f000a000 Uncommon trap: reason=array_check action=maybe_recompile pc=0x00007f61ed200cd4 method=java.util.ComparableTimSort.mergeHi(IIII)V @ 234 Event: 425.767 Thread 0x00007f61f000a000 Uncommon trap: reason=array_check action=maybe_recompile pc=0x00007f61ed226240 method=java.util.ComparableTimSort.mergeHi(IIII)V @ 642 Event: 425.768 Thread 0x00007f61f000a000 Uncommon trap: reason=array_check action=maybe_recompile pc=0x00007f61ed226240 method=java.util.ComparableTimSort.mergeHi(IIII)V @ 642 Event: 451.013 Thread 0x00007f61f000a000 Uncommon trap: reason=array_check action=maybe_recompile pc=0x00007f61ed229d20 method=java.util.ComparableTimSort.mergeHi(IIII)V @ 404 Event: 451.013 Thread 0x00007f61f000a000 Uncommon trap: reason=array_check action=maybe_recompile pc=0x00007f61ed229d20 method=java.util.ComparableTimSort.mergeHi(IIII)V @ 404 Event: 518.661 Thread 0x00007f61f000a000 Uncommon trap: reason=array_check action=maybe_recompile pc=0x00007f61ed22c5c8 method=java.util.ComparableTimSort.mergeHi(IIII)V @ 509 Event: 518.661 Thread 0x00007f61f000a000 Uncommon trap: reason=array_check action=maybe_recompile pc=0x00007f61ed22c5c8 method=java.util.ComparableTimSort.mergeHi(IIII)V @ 509 Event: 576.223 Thread 0x00007f61f000a000 Uncommon trap: reason=array_check action=maybe_recompile pc=0x00007f61ed22399c method=java.util.ComparableTimSort.mergeLo(IIII)V @ 129 Event: 626.762 Thread 0x00007f61f000a000 Uncommon trap: reason=array_check action=maybe_recompile pc=0x00007f61ed22399c method=java.util.ComparableTimSort.mergeLo(IIII)V @ 129 Event: 805.388 Thread 0x00007f61f000a000 Uncommon trap: reason=array_check action=maybe_recompile pc=0x00007f61ed232884 method=java.util.ComparableTimSort.mergeHi(IIII)V @ 160 Internal exceptions (10 events): Event: 95.779 Thread 0x00007f61f000a000 Threw 0x000000076e72f270 at /build/buildd/openjdk-7-7u55-2.4.7/build/openjdk/hotspot/src/share/vm/prims/jvm.cpp:1244 Event: 95.780 Thread 0x00007f61f000a000 Threw 0x000000076e732680 at /build/buildd/openjdk-7-7u55-2.4.7/build/openjdk/hotspot/src/share/vm/prims/jvm.cpp:1244 Event: 95.866 Thread 0x00007f61f000a000 Threw 0x000000076ea384b0 at /build/buildd/openjdk-7-7u55-2.4.7/build/openjdk/hotspot/src/share/vm/prims/jvm.cpp:1244 Event: 118.330 Thread 0x00007f61f000a000 Threw 0x0000000770f9b6f0 at /build/buildd/openjdk-7-7u55-2.4.7/build/openjdk/hotspot/src/share/vm/prims/jvm.cpp:1244 Event: 118.332 Thread 0x00007f61f000a000 Threw 0x0000000770fba0d8 at /build/buildd/openjdk-7-7u55-2.4.7/build/openjdk/hotspot/src/share/vm/prims/jvm.cpp:1244 Event: 118.528 Thread 0x00007f61f000a000 Threw 0x00000007713a1fc0 at /build/buildd/openjdk-7-7u55-2.4.7/build/openjdk/hotspot/src/share/vm/prims/jvm.cpp:1244 Event: 118.529 Thread 0x00007f61f000a000 Threw 0x00000007713a9628 at /build/buildd/openjdk-7-7u55-2.4.7/build/openjdk/hotspot/src/share/vm/prims/jvm.cpp:1244 Event: 118.533 Thread 0x00007f61f000a000 Threw 0x00000007713bea90 at /build/buildd/openjdk-7-7u55-2.4.7/build/openjdk/hotspot/src/share/vm/prims/jvm.cpp:1244 Event: 118.545 Thread 0x00007f61f000a000 Threw 0x00000007713e8238 at /build/buildd/openjdk-7-7u55-2.4.7/build/openjdk/hotspot/src/share/vm/prims/jvm.cpp:1244 Event: 118.546 Thread 0x00007f61f000a000 Threw 0x00000007713eb0f8 at /build/buildd/openjdk-7-7u55-2.4.7/build/openjdk/hotspot/src/share/vm/prims/jvm.cpp:1244 Events (10 events): Event: 972.069 Executing VM operation: RevokeBias done Event: 972.069 Executing VM operation: RevokeBias Event: 972.069 Executing VM operation: RevokeBias done Event: 972.069 Executing VM operation: RevokeBias Event: 972.069 Executing VM operation: RevokeBias done Event: 972.069 Executing VM operation: RevokeBias Event: 972.069 Executing VM operation: RevokeBias done Event: 972.069 Executing VM operation: RevokeBias Event: 972.296 Executing VM operation: RevokeBias done Event: 972.296 Executing VM operation: RevokeBias Dynamic libraries:[omitted] VM Arguments: jvm_args: -Xmx7200m java_command: [omitted] Launcher Type: SUN_STANDARD Environment Variables: [omitted] Signal Handlers: SIGSEGV: [libjvm.so+0x918620], sa_mask[0]=0x7ffbfeff, sa_flags=0x10000004 SIGBUS: [libjvm.so+0x918620], sa_mask[0]=0x7ffbfeff, sa_flags=0x10000004 SIGFPE: [libjvm.so+0x795e30], sa_mask[0]=0x7ffbfeff, sa_flags=0x10000004 SIGPIPE: [libjvm.so+0x795e30], sa_mask[0]=0x7ffbfeff, sa_flags=0x10000004 SIGXFSZ: [libjvm.so+0x795e30], sa_mask[0]=0x7ffbfeff, sa_flags=0x10000004 SIGILL: [libjvm.so+0x795e30], sa_mask[0]=0x7ffbfeff, sa_flags=0x10000004 SIGUSR1: SIG_DFL, sa_mask[0]=0x00000000, sa_flags=0x00000000 SIGUSR2: [libjvm.so+0x795cd0], sa_mask[0]=0x00000000, sa_flags=0x10000004 SIGHUP: [libjvm.so+0x795eb0], sa_mask[0]=0x7ffbfeff, sa_flags=0x10000004 SIGINT: [libjvm.so+0x795eb0], sa_mask[0]=0x7ffbfeff, sa_flags=0x10000004 SIGTERM: [libjvm.so+0x795eb0], sa_mask[0]=0x7ffbfeff, sa_flags=0x10000004 SIGQUIT: [libjvm.so+0x795eb0], sa_mask[0]=0x7ffbfeff, sa_flags=0x10000004 --------------- SYSTEM --------------- OS:Ubuntu 14.04 (trusty) uname:Linux 3.13.0-24-generic #46-Ubuntu SMP Thu Apr 10 19:11:08 UTC 2014 x86_64 libc:glibc 2.19 NPTL 2.19 rlimit: STACK 8192k, CORE 0k, NPROC 59937, NOFILE 4096, AS infinity load average:1.80 1.67 1.50 /proc/meminfo: MemTotal: 7693824 kB MemFree: 634168 kB Buffers: 12600 kB Cached: 290332 kB SwapCached: 0 kB Active: 6799656 kB Inactive: 151160 kB Active(anon): 6647936 kB Inactive(anon): 200 kB Active(file): 151720 kB Inactive(file): 150960 kB Unevictable: 0 kB Mlocked: 0 kB SwapTotal: 0 kB SwapFree: 0 kB Dirty: 36 kB Writeback: 0 kB AnonPages: 6647924 kB Mapped: 18848 kB Shmem: 236 kB Slab: 41348 kB SReclaimable: 32536 kB SUnreclaim: 8812 kB KernelStack: 848 kB PageTables: 17104 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 3846912 kB Committed_AS: 6744548 kB VmallocTotal: 34359738367 kB VmallocUsed: 14888 kB VmallocChunk: 34359719127 kB HardwareCorrupted: 0 kB AnonHugePages: 0 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB DirectMap4k: 7872512 kB DirectMap2M: 0 kB CPU:total 2 (16 cores per cpu, 2 threads per core) family 6 model 62 stepping 4, cmov, cx8, fxsr, mmx, sse, sse2, sse3, ssse3, sse4.1, sse4.2, popcnt, aes, erms, ht, tsc /proc/cpuinfo: processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 62 model name : Intel(R) Xeon(R) CPU E5-2670 v2 @ 2.50GHz stepping : 4 microcode : 0x415 cpu MHz : 2500.058 cache size : 25600 KB physical id : 1 siblings : 2 core id : 0 cpu cores : 1 apicid : 32 initial apicid : 32 fpu : yes fpu_exception : yes cpuid level : 13 wp : yes flags : fpu de tsc msr pae cx8 apic sep cmov pat clflush mmx fxsr sse sse2 ss ht syscall nx lm constant_tsc rep_good nopl pni pclmulqdq ssse3 cx16 sse4_1 sse4_2 popcnt tsc_deadline_timer aes rdrand hypervisor lahf_lm ida arat epb pln pts dtherm fsgsbase erms bogomips : 5000.11 clflush size : 64 cache_alignment : 64 address sizes : 46 bits physical, 48 bits virtual power management: processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 62 model name : Intel(R) Xeon(R) CPU E5-2670 v2 @ 2.50GHz stepping : 4 microcode : 0x415 cpu MHz : 2500.058 cache size : 25600 KB physical id : 1 siblings : 2 core id : 0 cpu cores : 1 apicid : 32 initial apicid : 32 fpu : yes fpu_exception : yes cpuid level : 13 wp : yes flags : fpu de tsc msr pae cx8 apic sep cmov pat clflush mmx fxsr sse sse2 ss ht syscall nx lm constant_tsc rep_good nopl pni pclmulqdq ssse3 cx16 sse4_1 sse4_2 popcnt tsc_deadline_timer aes rdrand hypervisor lahf_lm ida arat epb pln pts dtherm fsgsbase erms bogomips : 5000.11 clflush size : 64 cache_alignment : 64 address sizes : 46 bits physical, 48 bits virtual power management: Memory: 4k page, physical 7693824k(634168k free), swap 0k(0k free) vm_info: OpenJDK 64-Bit Server VM (24.51-b03) for linux-amd64 JRE (1.7.0_55-b14), built on Apr 17 2014 20:08:07 by "buildd" with gcc 4.8.2 time: Thu May 29 20:30:58 2014 elapsed time: 979 seconds 

Answer 1

由于运行时报告2.245gig free，并在需要1.104gig时报告失败，因此请求应该成功是合乎逻辑的。 但是当你需要1.104gig时，你真的需要一块连续的内存块。 当连续块不可用时，JVM会报告OutOfMemoryexception。

对堆碎片进行一些搜索。 堆碎片是你的根本问题。

一种可能的解决方案是使用nio字节缓冲区和allocateDirect。
内存分配在JVM堆空间之外。

来自JavaDoc：

可以通过调用此类的allocateDirect工厂方法来创建直接字节缓冲区。 与非直接缓冲区相比，此方法返回的缓冲区通常具有更高的分配和解除分配成本。 直接缓冲区的内容可能位于正常的垃圾收集堆之外，因此它们对应用程序的内存占用量的影响可能并不明显。 因此，建议直接缓冲区主要分配给受基础系统本机I / O操作影响的大型长期缓冲区。 通常，最好只在它们在程序性能上产生可测量的增益时才分配直接缓冲区。

Answer 2

正如其他人所提到的，你不应该创建一个大的，1千兆字节的二维数组，因为需要分配一块连续的内存来容纳它。 但是，您可以创建具有所需尺寸的数组数组 。 这是因为每个子数组都将在堆上独立初始化。

而不是这个：

 float[][] A = new float[NUM_SEQ_TOTAL_P1][NUM_SEQ_TOTAL_P2]; 

做这个：

 float[][] A = new float[NUM_SEQ_TOTAL_P1][]; for (int i = 0; i < NUM_SEQ_TOTAL_P1; i++) { A[i] = new float[NUM_SEQ_TOTAL_P2]; }