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The Checker Framework enhances Java's type system to make it more powerful and useful. This lets software developers detect and prevent errors in their Java programs. The Checker Framework includes compiler plug-ins ("checkers") that find bugs or verify their absence. It also permits you to write your own compiler plug-ins.

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package org.checkerframework.framework.util;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;

/** Utilities for executing external processes. */
public class ExecUtil {

    public static int execute(String[] cmd, OutputStream std, OutputStream err) {

        Redirection outRedirect = new Redirection(std, BLOCK_SIZE);
        Redirection errRedirect = new Redirection(err, BLOCK_SIZE);

        try {
            Process proc = Runtime.getRuntime().exec(cmd);
            outRedirect.redirect(proc.getInputStream());
            errRedirect.redirect(proc.getErrorStream());

            IOException stdExc = outRedirect.join();
            IOException errExc = errRedirect.join();
            int exitStatus = proc.waitFor();

            if (stdExc != null) {
                throw stdExc;
            }

            if (errExc != null) {
                throw errExc;
            }

            return exitStatus;

        } catch (InterruptedException e) {
            throw new RuntimeException("Exception executing command: " + String.join(" ", cmd), e);
        } catch (IOException e) {
            throw new RuntimeException("Exception executing command: " + String.join(" ", cmd), e);
        }
    }

    public static final int BLOCK_SIZE = 1024;

    public static class Redirection {
        private final char[] buffer;
        private final OutputStreamWriter out;

        private Thread thread;
        private IOException exception;

        public Redirection(OutputStream out, int bufferSize) {
            this.buffer = new char[bufferSize];
            this.out = new OutputStreamWriter(out);
        }

        public void redirect(InputStream inStream) {

            exception = null;

            this.thread =
                    new Thread(
                            () -> {
                                try (InputStreamReader in = new InputStreamReader(inStream)) {
                                    int read = 0;
                                    while (read > -1) {
                                        read = in.read(buffer);
                                        if (read > 0) {
                                            out.write(buffer, 0, read);
                                        }
                                    }
                                    out.flush();
                                } catch (IOException exc) {
                                    exception = exc;
                                }
                            });
            thread.start();
        }

        public IOException join() throws InterruptedException {
            thread.join();
            return exception;
        }
    }
}