Completely reworked the tests

src/test/resources/java/Performance.java

@@ -0,0 +1,55 @@
+/*
+ *  Copyright 2023 the original author or authors.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *   you may not use this file except in compliance with the License.
+ *   You may obtain a copy of the License at
+ *
+ *       https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package java;/**
+ * Performance class
+ *
+ * @author <a href="https://erik.thauvin.net/">Erik C. Thauvin</a>
+ * @since 1.0
+ */
+public class Performance {
+    public static void main(String[] as) {
+        for (int i = 0; i < 10; i++) {
+            Performance p = new Performance(); // Avoid this whenever you can it's really expensive
+        }
+    }
+
+
+    private boolean checkTrimEmpty(String str) {
+        for (int i = 0; i < str.length(); i++) {
+            if (!Character.isWhitespace(str.charAt(i))) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    void foo() {
+        StringBuffer sb = new StringBuffer();
+        sb.append("a");     // avoid this
+
+        String foo = " ";
+        StringBuffer buf = new StringBuffer();
+        buf.append("Hello"); // poor
+        buf.append(foo);
+        buf.append("World");
+
+        buf.append("Hello").append(" ").append("World");
+
+        StringBuffer sbuf = new StringBuffer("tmp = " + System.getProperty("java.io.tmpdir"));
+// poor
+    }
+}