Addressing review comments (adding a env variable to override temp directory)

java/org/rocksdb/NativeLibraryLoader.java

@@ -8,15 +8,18 @@ import java.io.*;
  * The shared library is extracted to a temp folder and loaded from there.
  */
 public class NativeLibraryLoader {
-
   private static String sharedLibraryName = "librocksdbjni.so";
   private static String tempFilePrefix = "librocksdbjni";
   private static String tempFileSuffix = ".so";
 
-  public static void loadLibraryFromJar()
+  public static void loadLibraryFromJar(String tmpDir)
       throws IOException {
+    File temp;
+    if(tmpDir == null || tmpDir.equals(""))
+      temp = File.createTempFile(tempFilePrefix, tempFileSuffix);
+    else
+      temp = new File(tmpDir+"/"+sharedLibraryName);
 
-    File temp = File.createTempFile(tempFilePrefix, tempFileSuffix);
     temp.deleteOnExit();
 
     if (!temp.exists()) {
@@ -31,13 +34,17 @@ public class NativeLibraryLoader {
       throw new RuntimeException(sharedLibraryName + " was not found inside JAR.");
     }
 
+    OutputStream os = null;
     try {
-      OutputStream os = new FileOutputStream(temp);
+      os = new FileOutputStream(temp);
       while ((readBytes = is.read(buffer)) != -1) {
         os.write(buffer, 0, readBytes);
       }
     } finally {
+      if(os != null)
         os.close();
+
+      if(is != null)
         is.close();
     }
 

java/org/rocksdb/RocksDB.java

@@ -20,7 +20,6 @@ import org.rocksdb.NativeLibraryLoader;
  * indicates sth wrong at the rocksdb library side and the call failed.
  */
 public class RocksDB extends RocksObject {
-
   public static final int NOT_FOUND = -1;
   private static final String[] compressionLibs_ = {
       "snappy", "z", "bzip2", "lz4", "lz4hc"};
@@ -29,12 +28,12 @@ public class RocksDB extends RocksObject {
     RocksDB.loadLibrary();
   }
 
-
   /**
    * Loads the necessary library files.
    * Calling this method twice will have no effect.
    */
   public static synchronized void loadLibrary() {
+    String tmpDir = System.getenv("ROCKSDB_SHAREDLIB_DIR");
     // loading possibly necessary libraries.
     for (String lib : compressionLibs_) {
       try {
@@ -45,7 +44,7 @@ public class RocksDB extends RocksObject {
     }
     try
     {
-      NativeLibraryLoader.loadLibraryFromJar();
+      NativeLibraryLoader.loadLibraryFromJar(tmpDir);
     }
     catch (IOException e)
     {