Hadoop - 2.7.1 - Native References

package org.apache.hadoop.io.nativeio;

NativeIO
SharedFileDescriptorFactory

  /**
   * Return true if the JNI-based native IO extensions are available.
   */
  public static boolean isAvailable() {
    return NativeCodeLoader.isNativeCodeLoaded() && nativeLoaded;
  }

// import org.apache.hadoop.util.NativeCodeLoader;

  static {

    // Try to load native hadoop library and set fallback flag appropriately

    if(LOG.isDebugEnabled()) {

      LOG.debug("Trying to load the custom-built native-hadoop library...");

    }

    try {

      System.loadLibrary("hadoop");

      LOG.debug("Loaded the native-hadoop library");

      nativeCodeLoaded = true;

    } catch (Throwable t) {

      // Ignore failure to load

      if(LOG.isDebugEnabled()) {

        LOG.debug("Failed to load native-hadoop with error: " + t);

        LOG.debug("java.library.path=" +

            System.getProperty("java.library.path"));

      }

    }

    

    if (!nativeCodeLoaded) {

      LOG.warn("Unable to load native-hadoop library for your platform... " +

               "using builtin-java classes where applicable");

    }

  }

hadoop-2.7.1-src/hadoop-hdfs-project/hadoop-hdfs/src/main/java/overview.html

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"A Java Development Kit. The Hadoop developers recommend Oracle Java 7. You may also use OpenJDK."

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