1.change a common scenario when user input expression without stopped thread (#210)

* 1.change a common scenario when user input expression  in debug console when the program is not stopped

* 1. format a better code style.

Author: andxu

check_style.xml

@@ -136,6 +136,7 @@
             <property name="allowNoEmptyLineBetweenFields" value="true"/>
             <property name="allowMultipleEmptyLines" value="false"/>
             <property name="allowMultipleEmptyLinesInsideClassMembers" value="false"/>
+            <property name="tokens" value="VARIABLE_DEF, METHOD_DEF"/>
         </module>
         <module name="SeparatorWrap">
             <property name="id" value="SeparatorWrapDot"/>
@@ -276,5 +277,16 @@
         <module name="CommentsIndentation"/>
         <module name="EmptyStatement"/>
         <module name="StringLiteralEquality"/>
+         <!-- Developer should probably bring up this issue with designer if ever it occurs. -->
+        <module name="EqualsHashCode">
+            <property name="severity" value="info" />
+        </module>
+        <!-- Only apply this to local variables; Designers seem to prefer using same parameter names as class members. -->
+        <module name="HiddenField">
+            <property name="tokens" value="VARIABLE_DEF"/>
+        </module>
+        
+        <module name="SimplifyBooleanExpression"/>
+        <module name="SimplifyBooleanReturn"/>
     </module>
 </module>

com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/adapter/handler/CompletionsHandler.java

@@ -11,6 +11,7 @@
 
 package com.microsoft.java.debug.core.adapter.handler;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
@@ -41,6 +42,14 @@ public List<Command> getTargetCommands() {
     @Override
     public CompletableFuture<Response> handle(Command command, Arguments arguments, Response response, IDebugAdapterContext context) {
         CompletionsArguments completionsArgs = (CompletionsArguments) arguments;
+
+        // completions should be illegal when frameId is zero, it is sent when the program is running, while during running we cannot resolve
+        // the completion candidates
+        if (completionsArgs.frameId == 0) {
+            response.body = new ArrayList<>();
+            return CompletableFuture.completedFuture(response);
+        }
+
         StackFrameReference stackFrameReference = (StackFrameReference) context.getRecyclableIdPool().getObjectById(completionsArgs.frameId);
 
         if (stackFrameReference == null) {