Databases
StackOverflow2013
Postsdbo
POScala SBT and JNI library
Body
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POScala SBT and JNI library
    text
    copied!<p>I am writing a simple app in <code>Scala</code> that uses a leveldb database through the <code>leveldbjni</code> library. My <code>build.sbt</code> file looks like this:</p> <pre><code>name := "Whatever" version := "1.0" scalaVersion := "2.10.2" libraryDependencies ++= Seq( "org.iq80.leveldb" % "leveldb-api" % "0.6", "org.fusesource.leveldbjni" % "leveldbjni-all" % "1.7" ) </code></pre> <p>An <code>Object</code> is then responsible for creating a database. Unfortunately if I run the program I get back a <code>java.lang.UnsatisfiedLinkError</code>, raised by the <code>hawtjni</code> library that <code>leveldbjni</code> exploits under the hood.</p> <p>The error can be triggered easily also from the scala console:</p> <pre><code>scala&gt; import java.io.File scala&gt; import org.iq80.leveldb._ scala&gt; import org.fusesource.leveldbjni.JniDBFactory._ scala&gt; factory.open(new File("test"), new Options().createIfMissing(true)) java.lang.UnsatisfiedLinkError: org.fusesource.leveldbjni.internal.NativeOptions.init()V at org.fusesource.leveldbjni.internal.NativeOptions.init(Native Method) at org.fusesource.leveldbjni.internal.NativeOptions.&lt;clinit&gt;(NativeOptions.java:54) at org.fusesource.leveldbjni.JniDBFactory$OptionsResourceHolder.init(JniDBFactory.java:98) at org.fusesource.leveldbjni.JniDBFactory.open(JniDBFactory.java:167) at .&lt;init&gt;(&lt;console&gt;:15) ... scala&gt; System getProperty "java.io.tmpdir" res2: String = /var/folders/1l/wj6yg_wd15sg_gcql001wchm0000gn/T/ </code></pre> <p>I can't understand what is going on since the library is getting correctly extracted from the jar file but it is not getting loaded for some reasons. </p> <pre><code>$ file /var/folders/1l/wj6yg_wd15sg_gcql001wchm0000gn/T/lib* /var/folders/1l/wj6yg_wd15sg_gcql001wchm0000gn/T/libleveldbjni-1.7.jnilib: Mach-O universal binary with 2 architectures /var/folders/1l/wj6yg_wd15sg_gcql001wchm0000gn/T/libleveldbjni-1.7.jnilib (for architecture x86_64): Mach-O 64-bit dynamically linked shared library x86_64 /var/folders/1l/wj6yg_wd15sg_gcql001wchm0000gn/T/libleveldbjni-1.7.jnilib (for architecture i386): Mach-O dynamically linked shared library i386 </code></pre> <p>I think the problem is probably related to the classloader that sbt employs but I am not sure since I am relatively new to scala.</p> <p><strong>UPDATE</strong></p> <p>Still didn't find what or who is the culprit. Anyway the library is actually found and correctly loaded, since I can execute the following commands:</p> <pre><code>scalac&gt; import org.fusesource.leveldbjni.internal.NativeDB scalac&gt; NativeDB.LIBRARY.load() </code></pre> <p>The error is somehow due to the <code>init()</code> function that according to the <code>hawtjni</code> <a href="http://fusesource.com/forge/sites/hawtjni/documentation/developer-guide.html" rel="noreferrer">documentation</a> is responsible for setting <em>all the static fields annotated as constant fields with the constant value</em>. The exception can still be triggered by typing:</p> <pre><code>scalac&gt; import org.fusesource.leveldbjni.internal.NativeOptions scalac&gt; new NativeOptions() java.lang.UnsatisfiedLinkError: org.fusesource.leveldbjni.internal.NativeOptions.init()V at org.fusesource.leveldbjni.internal.NativeOptions.init(Native Method) at org.fusesource.leveldbjni.internal.NativeOptions.&lt;clinit&gt;(NativeOptions.java:54) at .&lt;init&gt;(&lt;console&gt;:9) </code></pre>
 

Querying!

 
Guidance
An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload