Polarbear
A tool to help diagnose OutOfMemoryError conditions.
Polarbear helps track down the root cause of OutOfMemoryError exceptions in Java. When the JVM runs out of memory, polarbear will log detailed information about what threads are running and what objects are live to /tmp/oom.log for later review.
Status:
This is a very early stage project. It works for our needs. We haven't verified it works beyond that. Issue reports and patches are very much appreciated!
Installation
OS X:
gnumake J2SDK=/System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home OSNAME=darwin clean test
Ubuntu:
make J2SDK=/usr/lib/jvm/java-1.6.0-openjdk OSNAME=linux clean test
Running make will build a JVMTI library. You can enable with a command line flag like the following:
-agentpath:/path/to/liboutOfMemory.so=ImportantClass,AnotherImportantClass
This will produce the normal output (see Sample Output below) in addition to calculating retained sizes for ImportantClass and AnotherImportantClass instances.
polarbear shell
polarbear provides a limited repl on 8787 that allows you to interact directly.
Note: 8787 is not secure or fault tolerant and MUST be protected in other ways
> telnet localhost 8787
histogram
[...]
stats Lorg/apache/lucene/index/IndexWriter;
[...]
Sample Output
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
at java.lang.StringBuilder.toString(StringBuilder.java:430)
at Test.main(Test.java:16)
Initializing polarbear.
Performing retained size analysis for 2 classes:
HashMap
OOMList
About to throw an OutOfMemory error.
Suspending all threads except the current one.
Printing a heap histogram.
Heap View, Total of 799172 objects found.
Space Count Retained Class Signature
---------- ---------- ---------- ----------------------
31692904 396154 0 [C
Collecting references... Finding references to references... Aggregating references...
Level 1 referrers:
396191 Ljava/lang/String;
3 Ljava/lang/Thread;
1 Ljava/lang/ThreadLocal$ThreadLocalMap$Entry;
1 Ljava/lang/ref/Finalizer$FinalizerThread;
1 Ljava/lang/ref/Reference$ReferenceHandler;
2 Ljava/io/BufferedWriter;
1 Ljava/lang/StringBuilder;
Level 2 referrers:
313 [Ljava/lang/Object;
314 Ljava/util/HashMap$Entry;
166 Ljava/util/LinkedHashMap$Entry;
309 Ljava/util/Hashtable$Entry;
186 Ljava/util/LinkedList$Entry;
259 Ljava/lang/Integer;
8 Lsun/security/util/ObjectIdentifier;
48 Ljava/security/Provider$Service;
40 Ljava/net/URL;
59 [Ljava/lang/String;
93 Ljava/security/Provider$ServiceKey;
46 Ljava/security/Provider$UString;
31 Ljava/util/concurrent/ConcurrentHashMap$HashEntry;
30 Ljava/security/Provider$EngineDescription;
16 Ljava/util/jar/JarFile;
23 Lsun/security/x509/OIDMap$OIDInfo;
28 Ljava/io/ExpiringCache$Entry;
16 Ljava/io/ObjectStreamField;
19 Ljava/util/Locale;
18 Lsun/security/x509/RDN;
21 Lsun/security/x509/AVAKeyword;
4 Ljava/lang/reflect/Method;
17 Ljava/util/jar/Attributes$Name;
11 Lsun/security/jca/ProviderConfig;
4 Ljava/util/jar/JarFile$JarFileEntry;
1 Ljava/lang/ref/WeakReference;
4 Ljava/lang/OutOfMemoryError;
1 [Ljava/lang/ThreadLocal$ThreadLocalMap$Entry;
2 Lsun/security/provider/Sun;
3 Lsun/security/x509/X500Name;
7 Lsun/security/x509/NetscapeCertTypeExtension$MapEntry;
2 Ljava/lang/reflect/Field;
2 Lsun/nio/cs/MacRoman$Encoder;
2 Lsun/security/x509/X509CertImpl;
5 Lsun/security/jca/ServiceId;
4 Ljava/io/File;
1 Lsun/security/jca/ProviderList$1;
2 Ljava/lang/ThreadGroup;
2 Ljava/util/Properties;
4 Ljava/text/Normalizer$Form;
3 Lsun/misc/Signal;
3 Ljava/lang/RuntimePermission;
2 Ljava/security/AlgorithmParameters;
2 Ljava/io/PrintStream;
2 [Ljava/lang/Thread;
3 Ljava/nio/charset/CodingErrorAction;
1 Ljava/io/UnixFileSystem;
1 Ljava/lang/ArithmeticException;
1 Ljava/lang/ClassLoader$NativeLibrary;
1 Ljava/io/FilePermission;
1 Lsun/nio/cs/StandardCharsets;
2 Ljava/nio/ByteOrder;
1 Lcom/apple/java/Usage;
1 Ljava/lang/reflect/ReflectPermission;
1 Lsun/nio/cs/US_ASCII;
1 Lsun/security/provider/certpath/X509CertPath;
1 Lsun/nio/cs/UTF_8;
1 Lsun/nio/cs/MacRoman;
1 Lsun/security/x509/RFC822Name;
Level 3 referrers:
10 [Ljava/lang/Object;
62 [Ljava/util/HashMap$Entry;
49 Ljava/util/HashMap$Entry;
96 Ljava/util/LinkedHashMap$Entry;
6 Ljava/util/Hashtable$Entry;
102 Ljava/util/LinkedList$Entry;
13 [Ljava/util/Hashtable$Entry;
79 Ljava/math/BigInteger;
2 Ljava/lang/reflect/Constructor;
21 [Ljava/util/concurrent/ConcurrentHashMap$HashEntry;
1 [Ljava/lang/Integer;
17 Ljava/lang/ref/Finalizer;
2 Ljava/util/Vector;
23 Lsun/security/util/DerInputBuffer;
23 Lsun/security/util/DerValue;
16 Lsun/misc/URLClassPath$JarLoader;
7 [Ljava/lang/Class;
23 Ljava/util/ArrayList;
21 Lsun/security/x509/AVA;
19 Ljava/lang/Object;
16 Ljava/lang/Byte;
5 Ljava/lang/ref/WeakReference;
6 [Ljava/io/ObjectStreamField;
9 Lsun/misc/JarIndex;
6 Lsun/security/x509/AlgorithmId;
3 [Lsun/security/x509/RDN;
2 Lsun/security/x509/X509CertInfo;
2 Lsun/security/util/MemoryCache$SoftCacheEntry;
2 Lsun/nio/cs/StreamEncoder;
6 Ljava/util/concurrent/atomic/AtomicInteger;
4 Ljava/util/Date;
1 Ljava/util/jar/JarVerifier;
1 [Lsun/security/jca/ProviderConfig;
1 Lsun/misc/Launcher$ExtClassLoader;
2 Lsun/security/x509/AuthorityKeyIdentifierExtension;
1 Ljava/lang/ThreadLocal$ThreadLocalMap;
1 Lsun/misc/Launcher$AppClassLoader;
2 Lsun/misc/URLClassPath;
2 Lsun/security/x509/NetscapeCertTypeExtension;
2 Ljava/io/OutputStreamWriter;
2 Ljava/security/Permissions;
2 Lsun/security/x509/SubjectKeyIdentifierExtension;
2 Lsun/security/x509/CertificateValidity;
1 LTest$OOMList;
2 Lsun/security/x509/CertificateIssuerName;
2 Ljava/nio/charset/CoderResult;
1 [Ljava/io/File;
2 Lsun/security/provider/DSAParameters;
1 [Lsun/security/x509/NetscapeCertTypeExtension$MapEntry;
2 Lsun/security/x509/CertificateExtensions;
2 Lsun/security/jca/ProviderList;
2 Lsun/security/x509/CertificateSubjectName;
1 Ljava/security/ProtectionDomain;
1 Ljava/io/BufferedInputStream;
1 Lsun/nio/cs/StandardCharsets$Aliases;
1 Lsun/nio/cs/StandardCharsets$Cache;
1 Ljava/util/IdentityHashMap;
1 [Lsun/security/jca/ServiceId;
1 Lsun/nio/cs/StandardCharsets$Classes;
1 Lsun/security/x509/BasicConstraintsExtension;
1 [Ljava/text/Normalizer$Form;
1 Lsun/security/x509/KeyUsageExtension;
2 Lsun/security/x509/CertificateVersion;
2 Lsun/net/www/protocol/jar/Handler;
2 Ljava/lang/Boolean;
1 Ljava/security/CodeSource;
1 [Ljava/lang/ThreadGroup;
2 Lsun/security/x509/CertificateSerialNumber;
1 Ljava/lang/ref/Reference;
1 Lsun/security/x509/SubjectAlternativeNameExtension;
2 Lsun/security/x509/CertificateX509Key;
1 Ljava/util/concurrent/atomic/AtomicReferenceFieldUpdater$AtomicReferenceFieldUpdaterImpl;
2 Lsun/security/x509/CertificateAlgorithmId;
1 Ljava/security/BasicPermissionCollection;
1 Lsun/misc/URLClassPath$FileLoader;
1 Ljava/math/MutableBigInteger;
1 Ljava/security/CodeSigner;
1 Ljava/io/FilePermissionCollection;
1 Ljava/util/BitSet;
1 Lsun/misc/Launcher$Factory;
1 Lsun/net/www/protocol/file/Handler;
1 Ljava/util/jar/JavaUtilJarAccessImpl;
1 Lcom/apple/java/Usage$1;
1 Lsun/reflect/ReflectionFactory;
1 Lsun/security/x509/GeneralName;
1 Lsun/misc/Launcher;
12678432 396201 0 Ljava/lang/String;
5823928 356 0 [Ljava/lang/Object;
464552 660 0 Ljava/lang/Class;
124248 751 0 [B
59024 856 0 [S
39664 788 0 [I
16432 83 0 [Ljava/util/HashMap$Entry;
12064 377 0 Ljava/util/HashMap$Entry;
10720 268 0 Ljava/util/LinkedHashMap$Entry;
10080 315 0 Ljava/util/Hashtable$Entry;
6912 288 0 Ljava/util/LinkedList$Entry;
4144 259 0 Ljava/lang/Integer;
3600 75 474416 Ljava/util/HashMap;
3280 17 0 [Ljava/util/Hashtable$Entry;
3160 79 0 Ljava/math/BigInteger;
2736 114 0 Lsun/security/util/ObjectIdentifier;
2688 48 0 Ljava/security/Provider$Service;
2560 40 0 Ljava/net/URL;
2488 60 0 [Ljava/lang/String;
2448 102 0 Ljava/util/LinkedList;
2232 93 0 Ljava/security/Provider$ServiceKey;
1920 48 0 Ljava/util/concurrent/ConcurrentHashMap$Segment;
1584 22 0 Ljava/lang/reflect/Constructor;
1536 48 0 Ljava/util/concurrent/locks/ReentrantLock$NonfairSync;
1200 30 0 Ljava/lang/ref/SoftReference;
1192 48 0 [Ljava/util/concurrent/ConcurrentHashMap$HashEntry;
1104 46 0 Ljava/security/Provider$UString;
1040 1 0 [Ljava/lang/Integer;
1000 25 0 Ljava/lang/ref/Finalizer;
992 31 0 Ljava/util/concurrent/ConcurrentHashMap$HashEntry;
960 30 0 Ljava/security/Provider$EngineDescription;
896 16 0 Ljava/util/jar/JarFile;
784 7 0 Ljava/lang/Thread;
736 23 0 Ljava/util/Vector;
736 23 0 Lsun/security/util/DerInputBuffer;
736 23 0 Lsun/security/util/DerValue;
736 23 0 Lsun/security/x509/OIDMap$OIDInfo;
672 28 0 Ljava/io/ExpiringCache$Entry;
640 16 0 Lsun/misc/URLClassPath$JarLoader;
640 16 0 Ljava/io/ObjectStreamField;
608 19 0 Ljava/util/Locale;
592 3 0 [J
576 25 0 [Ljava/lang/Class;
576 12 0 Ljava/util/Hashtable;
552 23 0 Lsun/security/util/DerInputStream;
552 23 0 Ljava/util/ArrayList;
504 21 0 Lsun/security/x509/RDN;
504 21 0 Lsun/security/x509/AVAKeyword;
504 21 0 [Lsun/security/x509/AVA;
504 21 0 Lsun/security/x509/AVA;
440 5 0 Ljava/lang/reflect/Method;
408 17 0 Ljava/util/jar/Attributes$Name;
368 23 0 Ljava/lang/Object;
352 11 0 Lsun/security/jca/ProviderConfig;
352 11 0 Ljava/security/AccessControlContext;
344 3 0 [Ljava/math/BigInteger;
336 6 208576 Ljava/util/LinkedHashMap;
336 14 0 [Ljava/lang/Byte;
320 4 0 Ljava/util/jar/JarFile$JarFileEntry;
312 3 0 [D
256 16 0 Ljava/lang/Byte;
256 8 0 Ljava/lang/ref/WeakReference;
256 8 0 Ljava/lang/OutOfMemoryError;
240 3 0 [Ljava/lang/ThreadLocal$ThreadLocalMap$Entry;
240 3 0 [Ljava/util/concurrent/ConcurrentHashMap$Segment;
240 10 0 Lsun/reflect/NativeConstructorAccessorImpl;
224 9 0 [Ljava/io/ObjectStreamField;
216 9 0 Lsun/misc/JarIndex;
192 2 0 Lsun/security/provider/Sun;
192 4 0 Lsun/security/x509/X500Name;
192 6 0 Lsun/security/x509/AlgorithmId;
168 7 0 Lsun/security/x509/NetscapeCertTypeExtension$MapEntry;
160 10 0 Lsun/reflect/DelegatingConstructorAccessorImpl;
152 4 0 [Lsun/security/x509/RDN;
144 2 0 Ljava/lang/reflect/Field;
144 2 0 Lsun/nio/cs/MacRoman$Encoder;
144 2 0 Lsun/security/x509/X509CertImpl;
144 3 751160 Ljava/util/concurrent/ConcurrentHashMap;
128 4 0 Ljava/lang/ThreadLocal$ThreadLocalMap$Entry;
128 4 0 Ljava/lang/ref/ReferenceQueue;
120 5 0 Lsun/security/jca/ServiceId;
120 5 0 Ljava/io/FileDescriptor;
112 2 0 Lsun/security/x509/X509CertInfo;
112 1 0 Ljava/lang/ref/Finalizer$FinalizerThread;
112 1 0 Ljava/lang/ref/Reference$ReferenceHandler;
112 2 0 Lsun/security/util/MemoryCache$SoftCacheEntry;
112 2 0 Lsun/nio/cs/StreamEncoder;
112 2 0 Ljava/io/ExpiringCache$1;
112 4 0 [Z
96 3 0 Ljava/util/zip/Inflater;
96 2 0 Ljava/nio/HeapByteBuffer;
96 6 0 Ljava/lang/ref/ReferenceQueue$Lock;
96 3 0 Ljava/io/FileInputStream;
96 4 0 Ljava/io/File;
96 1 0 Lsun/security/jca/ProviderList$1;
96 2 0 Ljava/lang/ThreadGroup;
96 2 0 Ljava/io/BufferedWriter;
96 6 0 Ljava/util/concurrent/atomic/AtomicInteger;
96 3 0 Ljava/util/Stack;
96 4 0 Ljava/util/Date;
96 2 0 Ljava/util/Properties;
96 4 0 Ljava/text/Normalizer$Form;
88 1 0 [[Ljava/lang/Byte;
88 1 0 [Lsun/security/util/ObjectIdentifier;
88 1 0 Ljava/util/jar/JarVerifier;
80 1 0 [[B
80 2 0 Lsun/security/provider/DSAPublicKeyImpl;
80 2 0 Ljava/io/ExpiringCache;
80 2 0 [Lsun/security/jca/ProviderConfig;
80 1 0 Lsun/misc/Launcher$ExtClassLoader;
80 5 0 Ljava/lang/ThreadLocal;
80 2 0 Lsun/security/x509/AuthorityKeyIdentifierExtension;
72 3 0 Ljava/lang/ThreadLocal$ThreadLocalMap;
72 3 0 Lsun/misc/Signal;
72 3 0 Ljava/util/zip/ZStreamRef;
72 3 0 Ljava/lang/RuntimePermission;
72 1 0 Lsun/misc/Launcher$AppClassLoader;
64 1 0 [F
64 2 0 Lsun/misc/URLClassPath;
64 2 0 Ljava/security/AlgorithmParameters;
64 1 0 Lsun/security/provider/NativePRNG$RandomIO;
64 2 0 Lsun/security/x509/NetscapeCertTypeExtension;
64 2 0 Ljava/io/OutputStreamWriter;
64 4 0 Lsun/security/x509/KeyIdentifier;
64 2 0 Lsun/security/util/MemoryCache;
64 4 0 Ljava/util/HashMap$EntrySet;
64 2 0 Ljava/io/PrintStream;
64 2 0 Ljava/lang/ref/ReferenceQueue$Null;
64 2 0 Ljava/io/FileOutputStream;
64 2 0 Ljava/security/Permissions;
64 2 0 [Ljava/lang/Thread;
64 2 0 Lsun/security/x509/SubjectKeyIdentifierExtension;
56 1 0 [Ljava/lang/Runnable;
48 2 0 Lsun/security/x509/CertificateValidity;
48 2 50776680 LTest$OOMList;
48 2 0 Lsun/security/x509/CertificateIssuerName;
48 2 0 Ljava/nio/charset/CoderResult;
48 3 0 Lsun/text/normalizer/NormalizerBase$QuickCheckResult;
48 2 0 Lsun/misc/NativeSignalHandler;
48 2 0 [Ljava/io/File;
48 2 0 Lsun/security/provider/DSAParameters;
48 2 0 Ljava/io/BufferedOutputStream;
48 1 0 [Lsun/security/x509/NetscapeCertTypeExtension$MapEntry;
48 2 0 Lsun/security/x509/CertificateExtensions;
48 2 0 Lsun/security/util/BitArray;
48 2 0 Lsun/security/jca/ProviderList;
48 2 0 Lsun/security/x509/CertificateSubjectName;
48 2 0 Lsun/nio/cs/Surrogate$Parser;
48 3 0 Ljava/nio/charset/CodingErrorAction;
48 2 0 Lsun/security/jca/ProviderList$3;
48 2 0 Lsun/security/util/Cache$EqualByteArray;
40 1 0 Ljava/security/ProtectionDomain;
40 2 0 [Ljava/security/CodeSigner;
40 1 0 Ljava/io/BufferedInputStream;
40 1 0 Lsun/nio/cs/StandardCharsets$Aliases;
40 1 0 Lsun/nio/cs/StandardCharsets$Cache;
40 1 27544 Ljava/util/IdentityHashMap;
40 1 0 [Lsun/security/jca/ServiceId;
40 1 0 Lsun/nio/cs/StandardCharsets$Classes;
32 1 0 Ljava/lang/VirtualMachineError;
32 1 0 Ljava/util/Collections$SynchronizedMap;
32 1 0 [Ljava/lang/OutOfMemoryError;
32 1 0 Lsun/security/x509/BasicConstraintsExtension;
32 1 0 [Ljava/text/Normalizer$Form;
32 2 0 Lsun/security/x509/SerialNumber;
32 1 0 Ljava/lang/NullPointerException;
32 1 0 Lsun/security/x509/KeyUsageExtension;
32 1 0 Lsun/misc/SoftCache;
32 2 0 Lsun/security/x509/CertificateVersion;
32 2 0 Lsun/net/www/protocol/jar/Handler;
32 2 0 Ljava/lang/Boolean;
32 2 0 Ljava/lang/Shutdown$Lock;
32 1 0 Ljava/security/CodeSource;
32 1 0 [Ljava/lang/ThreadGroup;
32 2 0 Lsun/security/x509/CertificateSerialNumber;
32 1 0 Ljava/lang/ref/Reference;
32 1 0 Ljava/io/UnixFileSystem;
32 1 0 Lsun/security/x509/SubjectAlternativeNameExtension;
32 1 0 Ljava/lang/ArithmeticException;
32 1 0 Ljava/lang/ClassLoader$NativeLibrary;
32 1 0 Ljava/io/FilePermission;
32 2 0 Lsun/security/x509/CertificateX509Key;
32 2 0 Ljava/util/HashSet;
32 1 0 Ljava/util/concurrent/atomic/AtomicReferenceFieldUpdater$AtomicReferenceFieldUpdaterImpl;
32 1 0 Lsun/nio/cs/StandardCharsets;
32 2 0 Lsun/security/x509/CertificateAlgorithmId;
32 2 0 Ljava/nio/ByteOrder;
32 1 0 Ljava/security/BasicPermissionCollection;
24 1 0 Lcom/apple/java/Usage;
24 1 0 Ljava/lang/reflect/ReflectPermission;
24 1 0 Lsun/misc/URLClassPath$FileLoader;
24 1 0 Ljava/util/Collections$UnmodifiableRandomAccessList;
24 1 0 Lsun/nio/cs/US_ASCII;
24 1 0 Ljava/math/MutableBigInteger;
24 1 0 Ljava/util/Collections$EmptyMap;
24 1 0 Lsun/security/provider/certpath/X509CertPath;
24 1 0 Ljava/security/Policy$UnsupportedEmptyCollection;
24 1 0 Ljava/security/CodeSigner;
24 1 0 Lsun/nio/cs/UTF_8;
24 1 0 Ljava/io/FilePermissionCollection;
24 1 0 Ljava/lang/StringBuilder;
24 1 0 Ljava/util/Arrays$ArrayList;
24 1 0 Lsun/nio/cs/MacRoman;
24 1 0 Ljava/util/BitSet;
16 1 0 [Ljava/security/Provider;
16 1 0 Lsun/jkernel/DownloadManager$1;
16 1 0 Lsun/text/normalizer/NormalizerBase$NFKCMode;
16 1 0 Lsun/misc/Launcher$Factory;
16 1 0 Ljava/nio/charset/CoderResult$2;
16 1 0 Lsun/net/www/protocol/file/Handler;
16 1 0 Ljava/util/jar/JavaUtilJarAccessImpl;
16 1 0 Ljava/lang/System$2;
16 1 0 Ljava/lang/reflect/ReflectAccess;
16 1 0 Lsun/misc/FloatingDecimal$1;
16 1 0 Ljava/util/jar/JarVerifier$3;
16 1 0 Lsun/text/normalizer/NormalizerBase$Mode;
16 1 0 Ljava/util/Collections$EmptySet;
16 1 0 Ljava/util/Hashtable$EmptyEnumerator;
16 1 0 Lsun/misc/ASCIICaseInsensitiveComparator;
16 1 0 [Ljava/security/cert/Certificate;
16 1 0 Ljava/security/ProtectionDomain$Key;
16 1 0 Lcom/apple/java/Usage$1;
16 1 0 Ljava/lang/Runtime;
16 1 0 Ljava/security/AccessControlContext$1;
16 1 0 [Ljava/lang/StackTraceElement;
16 1 0 Lsun/text/normalizer/NormalizerBase$NFDMode;
16 1 0 Ljava/util/Collections$UnmodifiableCollection;
16 1 0 Ljava/util/Collections$EmptyList;
16 1 0 Ljava/lang/InheritableThreadLocal;
16 1 0 Ljava/nio/charset/CoderResult$1;
16 1 0 Lsun/security/x509/RFC822Name;
16 1 0 Lsun/reflect/ReflectionFactory;
16 1 0 Ljava/lang/Terminator$1;
16 1 0 Ljava/lang/ApplicationShutdownHooks$1;
16 1 0 Lsun/security/util/ByteArrayLexOrder;
16 1 0 Ljava/net/URLClassLoader$7;
16 1 0 [Ljava/security/Principal;
16 1 0 Lsun/security/util/ByteArrayTagOrder;
16 1 0 Lsun/security/x509/GeneralName;
16 1 0 Ljava/util/regex/Pattern$5;
16 1 0 Ljava/lang/String$CaseInsensitiveComparator;
16 1 0 Lsun/util/calendar/Gregorian;
16 1 0 Lsun/security/x509/GeneralNames;
16 1 0 Lsun/misc/Launcher;
16 1 0 Ljava/util/regex/Pattern$Node;
16 1 0 Ljava/lang/ref/Reference$Lock;
16 1 0 Lsun/text/normalizer/NormalizerBase$NFCMode;
16 1 0 Ljava/util/Collections$ReverseComparator;
16 1 0 Lsun/misc/Unsafe;
16 1 0 Lsun/text/normalizer/NormalizerBase$NFKDMode;
16 1 0 Ljava/util/Hashtable$EmptyIterator;
16 1 0 Ljava/security/ProtectionDomain$2;
16 1 0 Ljava/net/UnknownContentHandler;
16 1 0 Ljava/io/FileDescriptor$1;
16 1 0 Ljava/util/regex/Pattern$LastNode;
---------- ---------- ----------------------
Resuming threads.
Printing thread dump.
Dumping thread state for 4 threads
#1 - Signal Dispatcher - RUNNABLE
#2 - Finalizer - WAITING
at java.lang.Object.wait(Object.java)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134)
at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:159)
#3 - Reference Handler - WAITING
at java.lang.Object.wait(Object.java)
at java.lang.Object.wait(Object.java:485)
at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:116)
#4 - main - RUNNABLE - [OOM thrower]
at java.lang.StringBuilder.toString(StringBuilder.java:430)
at Test.main(Test.java:16)
License
Polarbear is based on Sun Microsystems sample JVMTI code, and follows the license rules issued by Sun. All modifications are released under the same license.
Polarbear?
If you were a fan of LOST, you may understand why "Out of memory" and polar bears are related thoughts for us.