Use StringBuilders instead of StringBuffers, close AsyncHttpClient#305

Author: Stephane Landelle

api/src/main/java/org/asynchttpclient/multipart/MultipartRequestEntity.java

@@ -142,7 +142,7 @@ public String getContentType() {
         if (contentType.contains("boundary="))
             return contentType;
         else {
-            StringBuffer buffer = new StringBuffer(contentType);
+            StringBuilder buffer = new StringBuilder(contentType);
             if (!contentType.endsWith(";"))
                 buffer.append(";");
             buffer.append(" boundary=");

api/src/main/java/org/asynchttpclient/resumable/PropertiesBasedResumableProcessor.java

@@ -90,7 +90,7 @@ public void save(Map<String, Long> map) {
     }
 
     private static String append(Map.Entry<String, Long> e) {
-        return new StringBuffer(e.getKey()).append("=").append(e.getValue()).append("\n").toString();
+        return new StringBuilder(e.getKey()).append("=").append(e.getValue()).append("\n").toString();
     }
 
     /**

api/src/main/java/org/asynchttpclient/util/AsyncHttpProviderUtils.java

@@ -505,7 +505,7 @@ private static void add(StringBuilder sb, String name, int val) {
 
     public static String constructUserAgent(Class<? extends AsyncHttpProvider> httpProvider,
                                             AsyncHttpClientConfig config) {
-        return new StringBuffer(config.getUserAgent())
+        return new StringBuilder(config.getUserAgent())
                 .append(' ')
                 .append('(')
                 .append(httpProvider.getSimpleName())

api/src/test/java/org/asynchttpclient/async/BasicAuthTest.java

@@ -473,7 +473,7 @@ public AbstractHandler configureHandler() throws Exception {
     }
 
     @Test(groups = { "standalone", "default_provider" }, enabled = false)
-    public void StringBufferBodyConsumerTest() throws Throwable {
+    public void StringBuilderBodyConsumerTest() throws Throwable {
 
         SimpleAsyncHttpClient client = new SimpleAsyncHttpClient.Builder().setRealmPrincipal(user).setRealmPassword(admin).setUrl(getTargetUrl()).setHeader("Content-Type", "text/html").build();
         try {

api/src/test/java/org/asynchttpclient/async/SimpleAsyncHttpClientTest.java

@@ -57,7 +57,7 @@ public void inpuStreamBodyConsumerTest() throws Throwable {
     }
 
     @Test(groups = { "standalone", "default_provider" })
-    public void StringBufferBodyConsumerTest() throws Throwable {
+    public void StringBuilderBodyConsumerTest() throws Throwable {
 
         SimpleAsyncHttpClient client = new SimpleAsyncHttpClient.Builder().setIdleConnectionInPoolTimeoutInMs(100).setMaximumConnectionsTotal(50).setRequestTimeoutInMs(5 * 60 * 1000).setUrl(getTargetUrl()).setHeader("Content-Type", "text/html").build();
         try {