refine collection creations (#1974)

arthas-spring-boot-starter/src/main/java/com/alibaba/arthas/spring/StringUtils.java

@@ -12,7 +12,7 @@ import java.util.Map.Entry;
 public class StringUtils {
 
 	public static Map<String, String> removeDashKey(Map<String, String> map) {
-		Map<String, String> result = new HashMap<String, String>();
+		Map<String, String> result = new HashMap<String, String>(map.size());
 
 		for (Entry<String, String> entry : map.entrySet()) {
 			String key = entry.getKey();

core/src/main/java/com/taobao/arthas/core/server/ArthasBootstrap.java

@@ -257,16 +257,19 @@ public class ArthasBootstrap {
          * https://github.com/alibaba/arthas/issues/986
          * </pre>
          */
-        Map<String, String> copyMap = new HashMap<String, String>();
+        Map<String, Object> copyMap;
         if (argsMap != null) {
-            copyMap.putAll(argsMap);
-        }
-        // 添加 arthas.home
-        if (!copyMap.containsKey(ARTHAS_HOME_PROPERTY)) {
+            copyMap = new HashMap<String, Object>(argsMap);
+            // 添加 arthas.home
+            if (!copyMap.containsKey(ARTHAS_HOME_PROPERTY)) {
+                copyMap.put(ARTHAS_HOME_PROPERTY, arthasHome());
+            }
+        } else {
+            copyMap = new HashMap<String, Object>(1);
             copyMap.put(ARTHAS_HOME_PROPERTY, arthasHome());
         }
 
-        MapPropertySource mapPropertySource = new MapPropertySource("args", (Map<String, Object>)(Object)copyMap);
+        MapPropertySource mapPropertySource = new MapPropertySource("args", copyMap);
         arthasEnvironment.addFirst(mapPropertySource);
 
         tryToLoadArthasProperties();

memorycompiler/src/main/java/com/taobao/arthas/compiler/DynamicCompilerException.java

@@ -42,7 +42,7 @@ public class DynamicCompilerException extends RuntimeException {
         List<Map<String, Object>> messages = new ArrayList<Map<String, Object>>();
         if (diagnostics != null) {
             for (Diagnostic<? extends JavaFileObject> diagnostic : diagnostics) {
-                Map<String, Object> message = new HashMap<String, Object>();
+                Map<String, Object> message = new HashMap<String, Object>(2);
                 message.put("line", diagnostic.getLineNumber());
                 message.put("message", diagnostic.getMessage(Locale.US));
                 messages.add(message);

tunnel-server/src/main/java/com/alibaba/arthas/tunnel/server/endpoint/ArthasEndpoint.java

@@ -20,7 +20,7 @@ public class ArthasEndpoint {
 
     @ReadOperation
     public Map<String, Object> invoke() {
-        Map<String, Object> result = new HashMap<String, Object>();
+        Map<String, Object> result = new HashMap<>(4);
 
         result.put("version", this.getClass().getPackage().getImplementationVersion());
         result.put("properties", arthasProperties);