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. 1 311536 method java/io/BufferedReader. 1 311536 method java/io/BufferedReader.close 1 311536 method java/io/BufferedWriter. 1 311536 method java/io/Console$1$1. 1 311536 method java/io/Console$1$1.run 1 311536 method java/io/Console$1. 1 311536 method java/io/Console$1.consoleRestoreHook 1 311536 method java/io/Console. 1 311536 method java/io/Console.access$600 1 311536 method java/io/DataInputStream. 1 311536 method java/io/DataInputStream.readFully 1 311536 method java/io/DeleteOnExitHook. 1 311536 method java/io/DeleteOnExitHook. 1 311536 method java/io/DeleteOnExitHook.hook 1 311536 method java/io/DeleteOnExitHook.run 1 [... 900 lines truncated ...] 311536 method java/io/ExpiringCache.get 18 311536 method java/lang/Class.desiredAssertionStatus 18 311536 method java/lang/Class.desiredAssertionStatus0 18 311536 method java/lang/ClassLoader.findLoadedClass 18 311536 method java/lang/ClassLoader.findLoadedClass0 18 311536 method java/io/BufferedReader.ensureOpen 19 311536 method java/lang/System.currentTimeMillis 19 311536 method java/nio/Buffer.limit 19 311536 method java/util/Locale. 19 311536 method java/util/Locale.createSingleton 19 311536 method java/util/concurrent/ConcurrentHashMap$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. 20 311536 method java/nio/ByteBuffer.array 20 311536 method java/util/AbstractList. 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$HashEntry.newArray 22 311536 method sun/misc/Unsafe.compareAndSwapInt 22 311536 method java/util/HashMap. 23 311536 method java/util/concurrent/ConcurrentHashMap$HashEntry. 23 311536 syscall stat64 23 311536 method java/nio/charset/CoderResult.isUnderflow 24 311536 method java/util/AbstractMap. 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. 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. 27 311536 method java/lang/ClassLoader.check 28 311536 method java/lang/ClassLoader.checkName 28 311536 method java/lang/ref/Reference. 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$Entry. 30 311536 method java/util/LinkedHashMap.get 30 311536 syscall priocntlsys 30 311536 method java/util/HashMap.put 33 311536 method java/util/Vector. 33 311536 method java/io/UnixFileSystem.normalize 34 311536 method java/lang/Class.getClassLoader0 34 311536 method java/lang/String.toLowerCase 34 311536 method sun/security/action/GetPropertyAction.run 34 311536 method java/nio/CharBuffer.arrayOffset 36 311536 method java/util/HashMap.getEntry 36 311536 method java/io/File. 37 311536 method java/io/UnixFileSystem.prefixLength 37 311536 method java/io/BufferedReader.readLine 38 311536 method java/util/concurrent/locks/AbstractOwnableSynchronizer.setExclusiveOwnerThread 38 311536 syscall resolvepath 38 311536 method java/lang/CharacterDataLatin1.toLowerCase 41 311536 method java/lang/CharacterDataLatin1.getProperties 43 311536 method java/security/AccessController.doPrivileged 43 311536 method java/util/Vector.size 43 311536 method java/nio/Buffer.position 44 311536 method java/nio/ByteBuffer.arrayOffset 44 311536 method java/lang/System.getProperty 48 311536 method java/util/Properties.getProperty 50 311536 method java/util/BitSet.expandTo 51 311536 method java/util/BitSet.set 51 311536 syscall pollsys 55 311536 method java/lang/System.checkKey 56 311536 method java/lang/Thread.currentThread 57 311536 method java/util/Hashtable$Entry. 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. 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. 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. 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. 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.