diff --git a/core/pom.xml b/core/pom.xml
index cd9264102f..cec6dc0e73 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -103,11 +103,6 @@ THE SOFTWARE.
       <groupId>org.connectbot.jbcrypt</groupId>
       <artifactId>jbcrypt</artifactId>
     </dependency>
-    <dependency> <!-- for compatibility only; all new code should use JNR. Not included into BOM due to the same reason -->
-      <groupId>org.jruby.ext.posix</groupId>
-      <artifactId>jna-posix</artifactId>
-      <version>1.0.3-jenkins-1</version>
-    </dependency>
     <dependency>
       <groupId>com.github.jnr</groupId>
       <artifactId>jnr-posix</artifactId>
diff --git a/core/src/main/java/hudson/os/PosixAPI.java b/core/src/main/java/hudson/os/PosixAPI.java
index 8d3a32d749..c9f40ac31b 100644
--- a/core/src/main/java/hudson/os/PosixAPI.java
+++ b/core/src/main/java/hudson/os/PosixAPI.java
@@ -1,10 +1,5 @@
 package hudson.os;
 
-import java.io.File;
-import java.io.InputStream;
-import java.io.PrintStream;
-import java.util.Map;
-import java.util.logging.Logger;
 import jnr.constants.platform.Errno;
 import jnr.posix.POSIX;
 import jnr.posix.POSIXFactory;
@@ -12,7 +7,6 @@ import jnr.posix.util.DefaultPOSIXHandler;
 
 /**
  * POSIX API wrapper.
- * Formerly used the jna-posix library, but this has been superseded by jnr-posix.
  * @author Kohsuke Kawaguchi
  */
 public class PosixAPI {
@@ -30,106 +24,13 @@ public class PosixAPI {
         if (posix == null) {
             posix = POSIXFactory.getPOSIX(new DefaultPOSIXHandler() {
                 @Override public void error(Errno error, String extraData) {
-                    throw new PosixException("native error " + error.description() + " " + extraData, convert(error));
+                    throw new PosixException("native error " + error.description() + " " + extraData);
                 }
                 @Override public void error(Errno error, String methodName, String extraData) {
-                    throw new PosixException("native error calling " + methodName + ": " + error.description() + " " + extraData, convert(error));
-                }
-                private org.jruby.ext.posix.POSIX.ERRORS convert(Errno error) {
-                    try {
-                        return org.jruby.ext.posix.POSIX.ERRORS.valueOf(error.name());
-                    } catch (IllegalArgumentException x) {
-                        return org.jruby.ext.posix.POSIX.ERRORS.EIO; // PosixException.message has real error anyway
-                    }
+                    throw new PosixException("native error calling " + methodName + ": " + error.description() + " " + extraData);
                 }
             }, true);
         }
         return posix;
     }
-
-    /**
-     * @deprecated use {@link #jnr} and {@link POSIX#isNative}
-     */
-    @Deprecated
-    public boolean isNative() {
-        return supportsNative();
-    }
-
-    /**
-     * @deprecated use {@link #jnr} and {@link POSIX#isNative}
-     */
-    @Deprecated
-    public static boolean supportsNative() {
-        return !(jnaPosix instanceof org.jruby.ext.posix.JavaPOSIX);
-    }
-
-    private static org.jruby.ext.posix.POSIX jnaPosix;
-    /** @deprecated Use {@link #jnr} instead. */
-    @Deprecated
-    public static synchronized org.jruby.ext.posix.POSIX get() {
-        if (jnaPosix == null) {
-            jnaPosix = org.jruby.ext.posix.POSIXFactory.getPOSIX(new org.jruby.ext.posix.POSIXHandler() {
-        @Override
-        public void error(org.jruby.ext.posix.POSIX.ERRORS errors, String s) {
-            throw new PosixException(s,errors);
-        }
-
-        @Override
-        public void unimplementedError(String s) {
-            throw new UnsupportedOperationException(s);
-        }
-
-        @Override
-        public void warn(WARNING_ID warning_id, String s, Object... objects) {
-            LOGGER.fine(s);
-        }
-
-        @Override
-        public boolean isVerbose() {
-            return true;
-        }
-
-        @Override
-        public File getCurrentWorkingDirectory() {
-            return new File(".").getAbsoluteFile();
-        }
-
-        @Override
-        public String[] getEnv() {
-            Map<String,String> envs = System.getenv();
-            String[] envp = new String[envs.size()];
-            
-            int i = 0;
-            for (Map.Entry<String,String> e : envs.entrySet()) {
-                envp[i++] = e.getKey()+'+'+e.getValue();
-            }
-            return envp;
-        }
-
-        @Override
-        public InputStream getInputStream() {
-            return System.in;
-        }
-
-        @Override
-        public PrintStream getOutputStream() {
-            return System.out;
-        }
-
-        @Override
-        public int getPID() {
-            // TODO
-            return 0;
-        }
-
-        @Override
-        public PrintStream getErrorStream() {
-            return System.err;
-        }
-    }, true);
-        }
-        return jnaPosix;
-    }
-
-    private static final Logger LOGGER = Logger.getLogger(PosixAPI.class.getName());
 }
diff --git a/core/src/main/java/hudson/os/PosixException.java b/core/src/main/java/hudson/os/PosixException.java
index 03cdd50e38..c32b9a3e6b 100644
--- a/core/src/main/java/hudson/os/PosixException.java
+++ b/core/src/main/java/hudson/os/PosixException.java
@@ -1,28 +1,17 @@
 package hudson.os;
 
-import org.jruby.ext.posix.POSIX.ERRORS;
-
 /**
  * Indicates an error during POSIX API call.
  * @see PosixAPI
  * @author Kohsuke Kawaguchi
  */
 public class PosixException extends RuntimeException {
-    private final ERRORS errors;
 
-    public PosixException(String message, ERRORS errors) {
+    public PosixException(String message) {
         super(message);
-        this.errors = errors;
     }
 
-    /** @deprecated Leaks reference to deprecated jna-posix API. */
-    @Deprecated
-    public ERRORS getErrorCode() {
-        return errors;
-    }
-
-    @Override
-    public String toString() {
-        return super.toString()+" "+errors;
+    public PosixException(String message, Throwable cause) {
+        super(message, cause);
     }
 }
diff --git a/core/src/main/java/hudson/util/IOUtils.java b/core/src/main/java/hudson/util/IOUtils.java
index 140efc89d0..b51435b49c 100644
--- a/core/src/main/java/hudson/util/IOUtils.java
+++ b/core/src/main/java/hudson/util/IOUtils.java
@@ -141,9 +141,7 @@ public class IOUtils {
                 return Util.permissionsToMode(Files.getPosixFilePermissions(fileToPath(f)));
             }
         } catch (IOException cause) {
-            PosixException e = new PosixException("Unable to get file permissions", null);
-            e.initCause(cause);
-            throw e;
+            throw new PosixException("Unable to get file permissions", cause);
         }
     }
 
diff --git a/licenseCompleter.groovy b/licenseCompleter.groovy
index 4dc5936c02..21c78e8f72 100644
--- a/licenseCompleter.groovy
+++ b/licenseCompleter.groovy
@@ -81,13 +81,4 @@ complete {
     match("net.jcip:jcip-annotations") {
         rewriteLicense([],ccby)
     }
-
-    //
-    // Choose from multi-licensed modules
-    //==========================================================================
-
-    match("*:jna-posix") {
-        accept("GNU Lesser General Public License Version 2.1")
-    }
-
 }