Fix to Ensure not isInterface requirement applied to all conditions (#695)

CHANGES.md

@@ -17,6 +17,7 @@ Release Notes.
 * Support for showing batch command details and ignoring PING commands in Redisson plugin.
 * Fix peer value of Master-Slave mode in Redisson plugin.
 * Support for tracing the callbacks of asynchronous methods in elasticsearch-6.x-plugin/elasticsearch-7.x-plugin.
+* Fixed the invalid issue in the isInterface method in PluginFinder.
 
 All issues and pull requests are [here](https://github.com/apache/skywalking/milestone/213?closed=1)
 

apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/plugin/PluginFinder.java

@@ -95,13 +95,14 @@ public class PluginFinder {
                 return nameMatchDefine.containsKey(target.getActualName());
             }
         };
-        judge = judge.and(not(isInterface()));
         for (AbstractClassEnhancePluginDefine define : signatureMatchDefine) {
             ClassMatch match = define.enhanceClass();
             if (match instanceof IndirectMatch) {
                 judge = judge.or(((IndirectMatch) match).buildJunction());
             }
         }
+        // Filter out all matchers returns to exclude pure interface types.
+        judge = not(isInterface()).and(judge);
         return new ProtectiveShieldMatcher(judge);
     }