JavaのProcessを使ってるとロックするあれ

LockedProcess.java

import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class LockedProcess {
    private static enum Option {
        CHILD(          "-child",        "Run as child"),
        MERGE_ERROR(    "-merge-error",  "Merge stderr stream into stdout stream"),
        CLOSE_STREAM(   "-close-stream", "Close all streams before calling waitFor."),
        HELP(           "-help", "Print this help.");

        public final String opt;
        public final String desc;
        private Option(String opt, String desc) {
            this.opt = opt;
            this.desc = desc;
        }
    }

    public static void main(String[] args) throws Exception {
        System.exit(new LockedProcess().run(args));
    }

    private int run(String[] args) throws Exception {
        CmdLine cl = CmdLine.parse(args);
        if (cl.hasHelp()) {
            printHelp(System.err);
            return 1;
        }
        if (cl.has(Option.CHILD)) {
            return runAsChild(cl);
        } else {
            return runAsParent(cl);
        }
    }

    private void printHelp(PrintStream out) {
        out.format("Usage: java %s [options] <repeat>%n", LockedProcess.class);
        for (Option o : Option.values()) {
            out.format("\t%-20s%s%n", o.opt, o.desc);
        }
    }

    private int runAsParent(CmdLine cl) throws Exception {
        List<String> args = new ArrayList<>();
        Collections.addAll(args,
            System.getProperty("java.home") + "/bin/java",
            LockedProcess.class.getName(),
            Option.CHILD.opt);
        args.addAll(cl.args);
        
        ProcessBuilder pb = new ProcessBuilder(args);
        if (cl.has(Option.MERGE_ERROR)) {
            pb.redirectErrorStream(true);
        }
        Process p = pb.start();
        if (cl.has(Option.CLOSE_STREAM)) {
            p.getInputStream().close();
            p.getErrorStream().close();
            p.getOutputStream().close();
        }
        int n = p.waitFor();
        System.out.println("status:" + n);
        if (!cl.has(Option.CLOSE_STREAM)) {
            drain(p.getInputStream(), System.out);
            drain(p.getErrorStream(), System.out);
        }
        return 0;
    }

    private int runAsChild(CmdLine cl) {
        String slen = or(get(cl.args, 0), "100");
        int len = Integer.parseInt(slen);
        for (int i = 0; i < len; i++) {
            System.out.println("stdout" + i);
            System.err.println("stderr" + i);
        }
        return 0;
    }

    private void drain(InputStream in, OutputStream out) throws Exception {
        for (;;) {
            byte[] b = new byte[128];
            int n = in.read(b);
            if (n <= 0) break;
            out.write(b, 0, n);
        }
    }

    private <T> T get(List<T> a, int i) {
        return i < a.size() ? a.get(i) : null;
    }

    private <T> T or(T x, T ifNull) {
        return x != null ? x : ifNull;
    }

    private static class CmdLine {
        public final Set<String> opts;
        public final List<String> args;
        public CmdLine(Set<String> opts, List<String> args) {
            this.opts = Collections.unmodifiableSet(new HashSet<>(opts));
            this.args = Collections.unmodifiableList(new ArrayList<>(args));
        }

        public boolean has(Option opt) {
            return opts.contains(opt.opt);
        }

        public boolean hasHelp() {
            List<String> helpOpts = Arrays.asList(Option.HELP.opt, "-h", "--help", "-help");
            return new HashSet<>(helpOpts).removeAll(opts);
        }

       public static CmdLine parse(String[] args) {
            Set<String> o = new HashSet<>();
            List<String> a = new ArrayList<>();
            for (int i = 0; i < args.length; i++) {
                if (args[i].startsWith("-")) {
                    o.add(args[i]);
                } else {
                    a.add(args[i]);
                }
            }
            return new CmdLine(o, a);
        }
    }
}

java LockedProcess 5000
java LockedProcess -help