diff --git a/src/main/java/org/apache/maven/shared/scriptinterpreter/BeanShellScriptInterpreter.java b/src/main/java/org/apache/maven/shared/scriptinterpreter/BeanShellScriptInterpreter.java
index 3699518..5f613f9 100644
--- a/src/main/java/org/apache/maven/shared/scriptinterpreter/BeanShellScriptInterpreter.java
+++ b/src/main/java/org/apache/maven/shared/scriptinterpreter/BeanShellScriptInterpreter.java
@@ -128,9 +128,7 @@ public Object evaluateScript(String script, Map<String, ?> globalVariables, Prin
                 }
             }
 
-            if (classLoader != null) {
-                engine.setClassLoader(classLoader);
-            }
+            engine.setClassLoader(classLoader);
 
             if (globalVariables != null) {
                 for (Map.Entry<String, ?> entry : globalVariables.entrySet()) {
@@ -159,8 +157,6 @@ public Object evaluateScript(String script, Map<String, ?> globalVariables, Prin
 
     @Override
     public void close() throws IOException {
-        if (classLoader != null) {
-            classLoader.close();
-        }
+        classLoader.close();
     }
 }
diff --git a/src/main/java/org/apache/maven/shared/scriptinterpreter/ScriptRunner.java b/src/main/java/org/apache/maven/shared/scriptinterpreter/ScriptRunner.java
index 2bc737f..1b1773d 100644
--- a/src/main/java/org/apache/maven/shared/scriptinterpreter/ScriptRunner.java
+++ b/src/main/java/org/apache/maven/shared/scriptinterpreter/ScriptRunner.java
@@ -111,7 +111,7 @@ public void setClassPath(List<String> classPath) {
      *                 default encoding.
      */
     public void setScriptEncoding(String encoding) {
-        this.encoding = (encoding != null && !encoding.isEmpty()) ? encoding : null;
+        this.encoding = encoding != null && !encoding.isEmpty() ? encoding : null;
     }
 
     /**
diff --git a/src/test/java/org/apache/maven/shared/scriptinterpreter/BeanShellScriptInterpreterTest.java b/src/test/java/org/apache/maven/shared/scriptinterpreter/BeanShellScriptInterpreterTest.java
index 35f64a5..b00a4cb 100644
--- a/src/test/java/org/apache/maven/shared/scriptinterpreter/BeanShellScriptInterpreterTest.java
+++ b/src/test/java/org/apache/maven/shared/scriptinterpreter/BeanShellScriptInterpreterTest.java
@@ -32,26 +32,28 @@
  *
  * @author Benjamin Bentmann
  */
-public class BeanShellScriptInterpreterTest {
+class BeanShellScriptInterpreterTest {
     @Test
-    public void testEvaluateScript() throws Exception {
+    void testEvaluateScript() throws Exception {
         ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ScriptInterpreter interpreter = new BeanShellScriptInterpreter();
-        assertEquals(
-                Boolean.TRUE,
-                interpreter.evaluateScript("System.out.print(\"Test\"); return true;", null, new PrintStream(out)));
+        try (ScriptInterpreter interpreter = new BeanShellScriptInterpreter()) {
+            assertEquals(
+                    Boolean.TRUE,
+                    interpreter.evaluateScript("System.out.print(\"Test\"); return true;", null, new PrintStream(out)));
+        }
         assertEquals("Test", out.toString());
     }
 
     @Test
-    public void testEvaluateScriptVars() throws Exception {
+    void testEvaluateScriptVars() throws Exception {
         Map<String, Object> vars = new HashMap<>();
         vars.put("testVar", "data");
         ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ScriptInterpreter interpreter = new BeanShellScriptInterpreter();
-        assertEquals(
-                Boolean.TRUE,
-                interpreter.evaluateScript("System.out.print(testVar); return true;", vars, new PrintStream(out)));
+        try (ScriptInterpreter interpreter = new BeanShellScriptInterpreter()) {
+            assertEquals(
+                    Boolean.TRUE,
+                    interpreter.evaluateScript("System.out.print(testVar); return true;", vars, new PrintStream(out)));
+        }
         assertEquals("data", out.toString());
     }
 }
diff --git a/src/test/java/org/apache/maven/shared/scriptinterpreter/GroovyScriptInterpreterTest.java b/src/test/java/org/apache/maven/shared/scriptinterpreter/GroovyScriptInterpreterTest.java
index cdc6158..0e97e2d 100644
--- a/src/test/java/org/apache/maven/shared/scriptinterpreter/GroovyScriptInterpreterTest.java
+++ b/src/test/java/org/apache/maven/shared/scriptinterpreter/GroovyScriptInterpreterTest.java
@@ -35,27 +35,29 @@
  *
  * @author Benjamin Bentmann
  */
-public class GroovyScriptInterpreterTest {
+class GroovyScriptInterpreterTest {
     @Test
-    public void testEvaluateScript() throws Exception {
+    void testEvaluateScript() throws Exception {
         ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ScriptInterpreter interpreter = new GroovyScriptInterpreter();
-        assertEquals(
-                Boolean.TRUE, interpreter.evaluateScript("print \"Test\"\nreturn true", null, new PrintStream(out)));
+        try (ScriptInterpreter interpreter = new GroovyScriptInterpreter()) {
+            assertEquals(
+                    Boolean.TRUE,
+                    interpreter.evaluateScript("print \"Test\"\nreturn true", null, new PrintStream(out)));
+        }
         assertEquals("Test", out.toString());
     }
 
     @Test
-    public void testEvaluateScriptWithDefaultClassPath() throws Exception {
+    void testEvaluateScriptWithDefaultClassPath() throws Exception {
         ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ScriptInterpreter interpreter = new GroovyScriptInterpreter();
-
-        assertEquals(
-                Boolean.TRUE,
-                interpreter.evaluateScript(
-                        "print getClass().getResource( \"/class-path.txt\" ).getPath().toURI().getPath()\nreturn true",
-                        null,
-                        new PrintStream(out)));
+        try (ScriptInterpreter interpreter = new GroovyScriptInterpreter()) {
+            assertEquals(
+                    Boolean.TRUE,
+                    interpreter.evaluateScript(
+                            "print getClass().getResource( \"/class-path.txt\" ).getPath().toURI().getPath()\nreturn true",
+                            null,
+                            new PrintStream(out)));
+        }
 
         String testClassPath =
                 new File("target/test-classes/class-path.txt").toURI().getPath();
@@ -63,19 +65,20 @@ public void testEvaluateScriptWithDefaultClassPath() throws Exception {
     }
 
     @Test
-    public void testEvaluateScriptWithCustomClassPath() throws Exception {
+    void testEvaluateScriptWithCustomClassPath() throws Exception {
         ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ScriptInterpreter interpreter = new GroovyScriptInterpreter();
+        try (ScriptInterpreter interpreter = new GroovyScriptInterpreter()) {
 
-        List<String> classPath = Collections.singletonList(new File("src/test-class-path").getAbsolutePath());
-        interpreter.setClassPath(classPath);
+            List<String> classPath = Collections.singletonList(new File("src/test-class-path").getAbsolutePath());
+            interpreter.setClassPath(classPath);
 
-        assertEquals(
-                Boolean.TRUE,
-                interpreter.evaluateScript(
-                        "print getClass().getResource( \"/class-path.txt\" ).getPath().toURI().getPath()\nreturn true",
-                        null,
-                        new PrintStream(out)));
+            assertEquals(
+                    Boolean.TRUE,
+                    interpreter.evaluateScript(
+                            "print getClass().getResource( \"/class-path.txt\" ).getPath().toURI().getPath()\nreturn true",
+                            null,
+                            new PrintStream(out)));
+        }
 
         String testClassPath =
                 new File("src/test-class-path/class-path.txt").toURI().getPath();
@@ -83,13 +86,14 @@ public void testEvaluateScriptWithCustomClassPath() throws Exception {
     }
 
     @Test
-    public void testEvaluateScriptVars() throws Exception {
+    void testEvaluateScriptVars() throws Exception {
         Map<String, Object> vars = new HashMap<>();
         vars.put("testVar", "data");
         ByteArrayOutputStream out = new ByteArrayOutputStream();
-        ScriptInterpreter interpreter = new GroovyScriptInterpreter();
-        assertEquals(
-                Boolean.TRUE, interpreter.evaluateScript("print testVar\nreturn true", vars, new PrintStream(out)));
+        try (ScriptInterpreter interpreter = new GroovyScriptInterpreter()) {
+            assertEquals(
+                    Boolean.TRUE, interpreter.evaluateScript("print testVar\nreturn true", vars, new PrintStream(out)));
+        }
         assertEquals("data", out.toString());
     }
 }