diff --git a/lib/Minify/ClosureCompiler.php b/lib/Minify/ClosureCompiler.php
index 238bfe3..d674508 100644
--- a/lib/Minify/ClosureCompiler.php
+++ b/lib/Minify/ClosureCompiler.php
@@ -129,7 +129,7 @@ class Minify_ClosureCompiler
             $this->getOptionsCommandLine($userOptions)
         );
 
-        return join(' ', $args) . ' ' . escapeshellarg($tmpFile);
+        return implode(' ', $args) . ' ' . escapeshellarg($tmpFile);
     }
 
     /**
diff --git a/lib/Minify/NailgunClosureCompiler.php b/lib/Minify/NailgunClosureCompiler.php
index a3fe291..89ee518 100644
--- a/lib/Minify/NailgunClosureCompiler.php
+++ b/lib/Minify/NailgunClosureCompiler.php
@@ -63,7 +63,7 @@ class Minify_NailgunClosureCompiler extends Minify_ClosureCompiler
         $server = array(
             self::$javaExecutable,
             '-server',
-            '-cp', join(':', $classPath),
+            '-cp', implode(':', $classPath),
             self::NG_SERVER,
         );
 
@@ -101,7 +101,7 @@ class Minify_NailgunClosureCompiler extends Minify_ClosureCompiler
 
     private function startServer()
     {
-        $serverCommand = join(' ', $this->getServerCommandLine());
+        $serverCommand = implode(' ', $this->getServerCommandLine());
         $psCommand = $this->shell("ps -o cmd= -C " . self::$javaExecutable);
         if (array_search($serverCommand, $psCommand) !== false) {
             // already started!