1 files changed, 51 insertions, 0 deletions
diff --git a/gerrit-pgm/src/main/java/com/google/gerrit/pgm/util/IoUtil.java b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/util/IoUtil.java
index 939885165b..f750748aa5 100644
--- a/gerrit-pgm/src/main/java/com/google/gerrit/pgm/util/IoUtil.java
+++ b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/util/IoUtil.java
@@ -14,9 +14,19 @@
 
 package com.google.gerrit.pgm.util;
 
+import com.google.common.collect.Sets;
+
+import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.Arrays;
+import java.util.Set;
 
 public final class IoUtil {
   public static void copyWithThread(final InputStream src,
@@ -42,6 +52,47 @@ public final class IoUtil {
     }.start();
   }
 
+  public static void loadJARs(File... jars) {
+    ClassLoader cl = IoUtil.class.getClassLoader();
+    if (!(cl instanceof URLClassLoader)) {
+      throw noAddURL("Not loaded by URLClassLoader", null);
+    }
+    @SuppressWarnings("resource")
+    URLClassLoader urlClassLoader = (URLClassLoader) cl;
+
+    Method addURL;
+    try {
+      addURL = URLClassLoader.class.getDeclaredMethod("addURL", URL.class);
+      addURL.setAccessible(true);
+    } catch (SecurityException e) {
+      throw noAddURL("Method addURL not available", e);
+    } catch (NoSuchMethodException e) {
+      throw noAddURL("Method addURL not available", e);
+    }
+
+    Set<URL> have = Sets.newHashSet(Arrays.asList(urlClassLoader.getURLs()));
+    for (File path : jars) {
+      try {
+        URL url = path.toURI().toURL();
+        if (have.add(url)) {
+          addURL.invoke(cl, url);
+        }
+      } catch (MalformedURLException e) {
+        throw noAddURL("addURL " + path + " failed", e);
+      } catch (IllegalArgumentException e) {
+        throw noAddURL("addURL " + path + " failed", e);
+      } catch (IllegalAccessException e) {
+        throw noAddURL("addURL " + path + " failed", e);
+      } catch (InvocationTargetException e) {
+        throw noAddURL("addURL " + path + " failed", e.getCause());
+      }
+    }
+  }
+
+  private static UnsupportedOperationException noAddURL(String m, Throwable why) {
+    String prefix = "Cannot extend classpath: ";
+    return new UnsupportedOperationException(prefix + m, why);
+  }
   private IoUtil() {
   }
 }