BAEL-1065 Simple performance check StringBuffer vs StringBuilder. (#2512)

* Code for Dependency Injection Article.

* Added Java based configuration. Downloaded formatter.xml and reformatted
all changed files. Manually changed tab into 4 spaces in XML
configuration files.

* BAEL-434 - Spring Roo project files generated by Spring Roo. No
formatting applied. Added POM, java and resources folders.

* Moved project from roo to spring-roo folder.

* BAEL-838 Initial code showing how to remove last char - helper class and tests.

* BAEL-838 Corrected Helper class and associated empty string test case. Added StringUtils.substing tests.

* BAEL-838 Refromatted code using formatter.xml. Added Assert.assertEquals import. Renamed test to follow convention. Reordered tests.

* BAEL-838 - Added regex method and updated tests.

* BAEL-838 Added new line examples.

* BAEL-838 Renamed RemoveLastChar class to StringHelper and added Java8 examples. Refactord code.

* BAEL-838 Changed method names

* BAEL-838 Tiny change to keep code consistant. Return null or empty.

* BAEL-838 Removed unresolved conflict.

* BAEL-821 New class that shows different rounding techniques. Updated POM.

* BAEL-821 - Added unit test for different round methods.

* BAEL-821 Changed test method name to follow the convention

* BAEL-821 Added more test and updated round methods.

* BAEL-837 - initial commit. A few examples of adding doubles.

* BAEL-837 - Couple of smaller changes

* BAEL-837 - Added jUnit test.

* BAEL-579 Updated Spring Cloud Version

I was getting error: java.lang.NoSuchMethodError:
org.springframework.cloud.config.environment.Environment
After version update, all is okay.

* BAEL-579 Added actuator to Cloud Config Client.

* BAEL-579 Enabled cloud bus and updated dependencies.

* BAEL-579 Config Client using Spring Cloud Bus.

* BAEL-579 Recreated Basic Config Server.

* BAEL-579 Recreated Config Client.

* BAEL-579 Removed test Git URL.

* BAEL-579 Added Actuator to Config Client

* BAEL-579 Added Spring Cloud Bus to Client.

* BAEL-579 Server changes for Spring Cloud Bus

Added dependencies and removed git.clone-on-start as this was causing
server to throw errors after git properties change.

* BAEL-579 Removed Git URL.

* Revert "BAEL-579 Updated Spring Cloud Version"

This reverts commit f775bf91e5.

* Revert "BAEL-579 Config Client using Spring Cloud Bus."

This reverts commit 1d96bc5761.

* Revert "BAEL-579 Enabled cloud bus and updated dependencies."

This reverts commit 7845da922d.

* Revert "BAEL-579 Added actuator to Cloud Config Client."

This reverts commit 076657a26a.

* BAEL-579 Added missing dependency versions.

* BAEL-579 Added missing dependency versions.

* Updated gitignore

* BAEL-1065 Simple performance check StringBuffer vs StringBuilder.

* BAEL-1065 Added JMH benchmarks

.gitignore

@@ -41,4 +41,5 @@ SpringDataInjectionDemo/.mvn/wrapper/maven-wrapper.properties
 spring-call-getters-using-reflection/.mvn/wrapper/maven-wrapper.properties
 
 spring-check-if-a-property-is-null/.mvn/wrapper/maven-wrapper.properties
-/vertx-and-rxjava/.vertx/
+*.springBeans
+

core-java/pom.xml

@@ -372,6 +372,31 @@
                     </arguments>
                 </configuration>
             </plugin>
+          
+            <plugin>
+				        <groupId>org.codehaus.mojo</groupId>
+				        <artifactId>exec-maven-plugin</artifactId>
+				        
+                <executions>
+					          <execution>
+						            <id>run-benchmarks</id>
+						            <phase>integration-test</phase>
+						            <goals>
+							              <goal>exec</goal>
+						            </goals>
+						            <configuration>
+							              <classpathScope>test</classpathScope>
+							              <executable>java</executable>
+							              <arguments>
+								                <argument>-classpath</argument>
+								                <classpath />
+								                <argument>org.openjdk.jmh.Main</argument>
+								                <argument>.*</argument>
+							              </arguments>
+						            </configuration>
+					          </execution>
+				        </executions>
+            </plugin>
         </plugins>
 
     </build>

core-java/src/main/java/com/baeldung/string/StringBufferStringBuilder.java

@@ -0,0 +1,46 @@
+package com.baeldung.string;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.RunnerException;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+public class StringBufferStringBuilder {
+
+    public static void main(String[] args) throws RunnerException {
+
+        Options opt = new OptionsBuilder()
+            .include(StringBufferStringBuilder.class.getSimpleName())
+            .build();
+
+        new Runner(opt).run();
+    }
+    
+    @State(Scope.Benchmark)
+    public static class MyState {
+        int iterations = 1000;
+        String initial = "abc";
+        String suffix = "def";
+    }
+     
+    @Benchmark
+    public StringBuffer benchmarkStringBuffer(MyState state) {
+        StringBuffer stringBuffer = new StringBuffer(state.initial);
+        for (int i = 0; i < state.iterations; i++) {
+            stringBuffer.append(state.suffix);
+        }
+        return stringBuffer;
+    }
+
+    @Benchmark
+    public StringBuilder benchmarkStringBuilder(MyState state) {
+        StringBuilder stringBuilder = new StringBuilder(state.initial);
+        for (int i = 0; i < state.iterations; i++) {
+            stringBuilder.append(state.suffix);
+        }
+        return stringBuilder;
+    }
+}