Read process output in Java without hanging the main thread

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;

/**
 * 
 * @author chenjianjx (Copied from CXF)
 *
 */
public class StreamPrinter extends Thread {
  InputStream is;
  String msg;
  OutputStream os;

  public StreamPrinter(InputStream stream, String type) {
    this(stream, type, null);
  }

  public StreamPrinter(InputStream stream, String type, OutputStream redirect) {
    is = stream;
    msg = type;
    os = redirect;
  }

  public void run() {
    try {
      PrintWriter pw = null;
      if (os != null) {
        pw = new PrintWriter(os);
      }
      InputStreamReader isr = new InputStreamReader(is);
      BufferedReader br = new BufferedReader(isr);
      String line = br.readLine();
      while (line != null) {
        if (pw != null) {
          pw.println(msg + " " + line);
        }
        line = br.readLine();
      }
      if (pw != null) {
        pw.flush();
      }
    } catch (IOException ioe) {
      throw new RuntimeException(ioe);
    }
  }
}
/**
 * 
 * @author chenjianjx
 * 
 */

public class SystemProcessException extends Exception {

  private int returnCode;
  private String consoleOutput;

  /**
   * 
   */
  private static final long serialVersionUID = -6904952219344675845L;

  public SystemProcessException(int returnCode, String consoleOutput) {
    super();
    this.returnCode = returnCode;
    this.consoleOutput = consoleOutput;
  }

  public int getReturnCode() {
    return returnCode;
  }

  public String getConsoleOutput() {
    return consoleOutput;
  }

}
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;

import org.jaxws.util.io.StreamPrinter;

/**
 * Spawning a process from the OS
 * 
 * @author chenjianjx
 * 
 */
public class SystemProcessUtils {

  /**
   * execture a program and returns console output
   */
  public static String exec(String[] cmdArray) throws SystemProcessException {

    try {
      Process p = Runtime.getRuntime().exec(cmdArray);
      ByteArrayOutputStream output = new ByteArrayOutputStream();
      Thread errStreamThread = collectErrorStream(p, output);
      Thread inputStreamThread = collectInputStream(p, output);
      int returningCode = p.waitFor();
      int timeout = 60000;
      if (errStreamThread != null) {
        errStreamThread.join(timeout);
      }
      if (inputStreamThread != null) {
        inputStreamThread.join(timeout);
      }
      String consoleOutput = new String(output.toByteArray());
      System.out.println(consoleOutput);
      if (returningCode != 0) {
        throw new SystemProcessException(returningCode, consoleOutput);
      }
      return consoleOutput;
    } catch (IOException e) {
      throw new IllegalStateException(e);
    } catch (InterruptedException e) {
      throw new IllegalStateException(e);
    }
  }

  private static StreamPrinter collectInputStream(Process p, OutputStream out) {
    if (p.getInputStream() != null) {
      StreamPrinter infoStreamPrinter = new StreamPrinter(p.getInputStream(), "[INFO]", out);
      infoStreamPrinter.start();
      return infoStreamPrinter;
    }
    return null;
  }

  private static StreamPrinter collectErrorStream(Process p, OutputStream out) {
    if (p.getErrorStream() != null) {
      StreamPrinter errorStreamPrinter = new StreamPrinter(p.getErrorStream(), "[ERROR]", out);
      errorStreamPrinter.start();
      return errorStreamPrinter;
    }
    return null;
  }

}

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