Seeing all the system calls that were made by a Java program

Question

How can I see which system calls my Java program is making? Is there a tool that will do this on Linux?

Could you use `strace java your_program`? – chrisaycock Apr 30 '12 at 13:55 — chrisaycock, Apr 30 '12 at 13:55
I tried it and it worked.Thanks – Ragini Apr 30 '12 at 15:25 — Ragini, Apr 30 '12 at 15:25

score 17 · Answer 1 · edited Mar 01 '21 at 19:10

Use strace. But there is is trick for my case. Option -f is needed and is the same as --follow-forks. For example, the following code:

public class Foo {
    public static void main (String [] args) {
        System.out.println("XXX");    
    }
}

After running javac Foo.java to compile it, strace java Foo 2>&1 | grep write print nothing. But strace -f java Foo 2>&1 | grep write prints:

[pid 11655] write(3, "0x63", 4)         = 4
[pid 11655] write(3, "\0", 1)           = 1
[pid 11655] write(3, "\0", 1)           = 1
[pid 11655] write(3, "\0", 1)           = 1
[pid 11655] write(3, "\0", 1)           = 1
[pid 11655] write(3, "\0", 1)           = 1
[pid 11655] write(3, "\0", 1)           = 1
[pid 11655] write(3, "\0", 1)           = 1
[pid 11655] write(3, "\0", 1)           = 1
[pid 11655] write(1, "XXX", 3XXX)          = 3
[pid 11655] write(1, "\n", 1

[pid 11655] write(1, "XXX", 3XXX) = 3 shows the system call made for System.out.println("XXX").

score 16 · Accepted Answer · edited Mar 01 '21 at 19:10

16

Use strace:

strace -f java your_program

or

strace -f -p <pid of your java program>

edited Mar 01 '21 at 19:10

rogerdpack

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answered Apr 30 '12 at 15:58

chrisaycock

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score 1 · Answer 3 · answered Apr 30 '12 at 13:56

1

see ltrace http://linux.die.net/man/1/ltrace

answered Apr 30 '12 at 13:56

Luca

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ptrace might be more useful in this case – Mike Kwan Apr 30 '12 at 14:03
4

@MikeKwan `ltrace` is for library function calls and `ptrace` is to examine other process' memory. `strace` is the one for system calls. – Pavan Manjunath Apr 30 '12 at 14:32

Seeing all the system calls that were made by a Java program

3 Answers3

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