The following are examples of j_syscalls.d.

This is a simple script to count executed Java methods and system calls.
Here it traces an example program, Code/Java/Func_abc.

# j_syscalls.d -c 'java -XX:+ExtendedDTraceProbes Func_abc'
Tracing... Hit Ctrl-C to end.
Function A
Function B
Function C
    PID TYPE     NAME                                                    COUNT
 311536 method   Func_abc.func_a                                             1
 311536 method   Func_abc.func_b                                             1
 311536 method   Func_abc.func_c                                             1
 311536 method   Func_abc.main                                               1
 311536 method   java/io/BufferedInputStream.<clinit>                        1
 311536 method   java/io/BufferedReader.<clinit>                             1
 311536 method   java/io/BufferedReader.close                                1
 311536 method   java/io/BufferedWriter.<clinit>                             1
 311536 method   java/io/Console$1$1.<init>                                  1
 311536 method   java/io/Console$1$1.run                                     1
 311536 method   java/io/Console$1.<init>                                    1
 311536 method   java/io/Console$1.consoleRestoreHook                        1
 311536 method   java/io/Console.<clinit>                                    1
 311536 method   java/io/Console.access$600                                  1
 311536 method   java/io/DataInputStream.<init>                              1
 311536 method   java/io/DataInputStream.readFully                           1
 311536 method   java/io/DeleteOnExitHook.<clinit>                           1
 311536 method   java/io/DeleteOnExitHook.<init>                             1
 311536 method   java/io/DeleteOnExitHook.hook                               1
 311536 method   java/io/DeleteOnExitHook.run                                1
[... 900 lines truncated ...]
 311536 method   java/io/ExpiringCache.get                                  18
 311536 method   java/lang/Class.desiredAssertionStatus                     18
 311536 method   java/lang/Class.desiredAssertionStatus0                    18
 311536 method   java/lang/ClassLoader.findLoadedClass                      18
 311536 method   java/lang/ClassLoader.findLoadedClass0                     18
 311536 method   java/io/BufferedReader.ensureOpen                          19
 311536 method   java/lang/System.currentTimeMillis                         19
 311536 method   java/nio/Buffer.limit                                      19
 311536 method   java/util/Locale.<init>                                    19
 311536 method   java/util/Locale.createSingleton                           19
 311536 method   java/util/concurrent/ConcurrentHashMap$Segment.put         19
 311536 method   java/util/concurrent/ConcurrentHashMap.put                 19
 311536 method   java/util/concurrent/locks/AbstractQueuedSynchronizer.compareAndSetState       19
 311536 method   java/util/concurrent/locks/AbstractQueuedSynchronizer.release       19
 311536 method   java/util/concurrent/locks/AbstractQueuedSynchronizer.setState       19
 311536 method   java/util/concurrent/locks/ReentrantLock$NonfairSync.lock       19
 311536 method   java/util/concurrent/locks/ReentrantLock$Sync.tryRelease       19
 311536 method   java/util/concurrent/locks/ReentrantLock.lock              19
 311536 method   java/util/concurrent/locks/ReentrantLock.unlock            19
 311536 method   java/io/ObjectStreamField.<init>                           20
 311536 method   java/nio/ByteBuffer.array                                  20
 311536 method   java/util/AbstractList.<init>                              20
 311536 method   java/util/BitSet.get                                       20
 311536 method   java/util/concurrent/ConcurrentHashMap.hash                20
 311536 method   java/util/concurrent/ConcurrentHashMap.segmentFor          20
 311536 method   sun/misc/VM.isBooted                                       20
 311536 syscall  memcntl                                                    20
 311536 method   java/io/File.getName                                       21
 311536 method   java/io/UnixFileSystem.getBooleanAttributes                21
 311536 method   java/io/UnixFileSystem.getBooleanAttributes0               21
 311536 method   java/lang/StringBuffer.append                              21
 311536 method   java/nio/charset/Charset.atBugLevel                        21
 311536 method   java/util/concurrent/ConcurrentHashMap$HashEntry.newArray       22
 311536 method   sun/misc/Unsafe.compareAndSwapInt                          22
 311536 method   java/util/HashMap.<init>                                   23
 311536 method   java/util/concurrent/ConcurrentHashMap$HashEntry.<init>       23
 311536 syscall  stat64                                                     23
 311536 method   java/nio/charset/CoderResult.isUnderflow                   24
 311536 method   java/util/AbstractMap.<init>                               24
 311536 method   java/util/Vector.elementAt                                 24
 311536 syscall  munmap                                                     24
 311536 method   java/lang/Class.getClassLoader                             25
 311536 syscall  lwp_sigmask                                                25
 311536 syscall  sigaction                                                  25
 311536 method   java/util/AbstractCollection.<init>                        26
 311536 method   java/util/ArrayList.add                                    26
 311536 method   java/util/ArrayList.ensureCapacity                         26
 311536 method   java/lang/ClassLoader.loadClass                            27
 311536 method   java/net/URL.<init>                                        27
 311536 method   java/lang/ClassLoader.check                                28
 311536 method   java/lang/ClassLoader.checkName                            28
 311536 method   java/lang/ref/Reference.<init>                             28
 311536 method   java/lang/String.endsWith                                  29
 311536 method   sun/misc/VM.allowArraySyntax                               29
 311536 method   java/io/ExpiringCache.entryFor                             30
 311536 method   java/io/UnixFileSystem.resolve                             30
 311536 method   java/util/HashMap$Entry.<init>                             30
 311536 method   java/util/LinkedHashMap.get                                30
 311536 syscall  priocntlsys                                                30
 311536 method   java/util/HashMap.put                                      33
 311536 method   java/util/Vector.<init>                                    33
 311536 method   java/io/UnixFileSystem.normalize                           34
 311536 method   java/lang/Class.getClassLoader0                            34
 311536 method   java/lang/String.toLowerCase                               34
 311536 method   sun/security/action/GetPropertyAction.run                  34
 311536 method   java/nio/CharBuffer.arrayOffset                            36
 311536 method   java/util/HashMap.getEntry                                 36
 311536 method   java/io/File.<init>                                        37
 311536 method   java/io/UnixFileSystem.prefixLength                        37
 311536 method   java/io/BufferedReader.readLine                            38
 311536 method   java/util/concurrent/locks/AbstractOwnableSynchronizer.setExclusiveOwnerThread       38
 311536 syscall  resolvepath                                                38
 311536 method   java/lang/CharacterDataLatin1.toLowerCase                  41
 311536 method   java/lang/CharacterDataLatin1.getProperties                43
 311536 method   java/security/AccessController.doPrivileged                43
 311536 method   java/util/Vector.size                                      43
 311536 method   java/nio/Buffer.position                                   44
 311536 method   java/nio/ByteBuffer.arrayOffset                            44
 311536 method   java/lang/System.getProperty                               48
 311536 method   java/util/Properties.getProperty                           50
 311536 method   java/util/BitSet.expandTo                                  51
 311536 method   java/util/BitSet.set                                       51
 311536 syscall  pollsys                                                    55
 311536 method   java/lang/System.checkKey                                  56
 311536 method   java/lang/Thread.currentThread                             57
 311536 method   java/util/Hashtable$Entry.<init>                           57
 311536 method   java/util/Hashtable.get                                    59
 311536 method   java/util/Hashtable.put                                    63
 311536 method   java/util/BitSet.checkInvariants                           71
 311536 method   java/util/BitSet.wordIndex                                 72
 311536 method   java/lang/StringBuilder.<init>                             73
 311536 method   java/lang/StringBuilder.toString                           73
 311536 method   java/lang/AbstractStringBuilder.expandCapacity             81
 311536 method   java/util/HashMap.hash                                     81
 311536 method   java/util/HashMap.indexFor                                 81
 311536 method   java/lang/AbstractStringBuilder.<init>                     82
 311536 method   java/lang/Character.toLowerCase                            82
 311536 method   java/lang/String.startsWith                                83
 311536 method   java/util/Arrays.copyOf                                    87
 311536 method   java/lang/String.lastIndexOf                               90
 311536 method   java/lang/String.substring                                 94
 311536 syscall  brk                                                       102
 311536 syscall  ioctl                                                     103
 311536 method   java/util/Arrays.copyOfRange                              107
 311536 syscall  mmap                                                      127
 311536 syscall  open                                                      129
 311536 syscall  close                                                     133
 311536 method   java/lang/String.getChars                                 156
 311536 method   java/lang/System.getSecurityManager                       174
 311536 method   java/lang/String.<init>                                   175
 311536 syscall  xstat                                                     188
 311536 method   java/lang/String.equals                                   202
 311536 method   java/lang/Math.min                                        208
 311536 method   java/lang/String.hashCode                                 213
 311536 syscall  lwp_exit                                                  291
 311536 method   java/lang/String.indexOf                                  302
 311536 method   java/lang/System.arraycopy                                360
 311536 method   java/lang/StringBuilder.append                            545
 311536 method   java/lang/AbstractStringBuilder.append                    561
 311536 syscall  llseek                                                    664
 311536 syscall  read                                                      668
 311536 method   java/lang/Object.<init>                                   823
 311536 method   java/lang/String.charAt                                  1987

While tracing there were numerous system calls made, including 668 reads()'s,
and 664 llseek()'s.  Many Java methods were also called, with 1987
java/lang/String.charAt being the most of a particular kind.

This script can provide an insight to how an application is interacting
with the system, by providing both application method calls and
system calls in the same output.


