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.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$Entry.<init> 30
311536 method java/util/LinkedHashMap.get 30
311536 syscall priocntlsys 30
311536 method java/util/HashMap.put 33
311536 method java/util/Vector.<init> 33
311536 method java/io/UnixFileSystem.normalize 34
311536 method java/lang/Class.getClassLoader0 34
311536 method java/lang/String.toLowerCase 34
311536 method sun/security/action/GetPropertyAction.run 34
311536 method java/nio/CharBuffer.arrayOffset 36
311536 method java/util/HashMap.getEntry 36
311536 method java/io/File.<init> 37
311536 method java/io/UnixFileSystem.prefixLength 37
311536 method java/io/BufferedReader.readLine 38
311536 syscall resolvepath 38
311536 method java/lang/CharacterDataLatin1.toLowerCase 41
311536 method java/lang/CharacterDataLatin1.getProperties 43
311536 method java/security/AccessController.doPrivileged 43
311536 method java/util/Vector.size 43
311536 method java/nio/Buffer.position 44
311536 method java/nio/ByteBuffer.arrayOffset 44
311536 method java/lang/System.getProperty 48
311536 method java/util/Properties.getProperty 50
311536 method java/util/BitSet.expandTo 51
311536 method java/util/BitSet.set 51
311536 syscall pollsys 55
311536 method java/lang/System.checkKey 56
311536 method java/lang/Thread.currentThread 57
311536 method java/util/Hashtable$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.