Fix potential StackOverFlowError on regexp

dd-java-agent/instrumentation/trace-annotation/src/main/java/datadog/trace/instrumentation/trace_annotation/TraceConfigInstrumentation.java

@@ -2,22 +2,22 @@ package datadog.trace.instrumentation.trace_annotation;
 
 import static datadog.trace.agent.tooling.ByteBuddyElementMatchers.safeHasSuperType;
 import static net.bytebuddy.matcher.ElementMatchers.named;
-
 import com.google.auto.service.AutoService;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
 import datadog.trace.agent.tooling.Instrumenter;
 import datadog.trace.api.Config;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Set;
 import lombok.extern.slf4j.Slf4j;
 import net.bytebuddy.agent.builder.AgentBuilder;
 import net.bytebuddy.description.method.MethodDescription;
 import net.bytebuddy.description.type.TypeDescription;
 import net.bytebuddy.matcher.ElementMatcher;
 
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
 /**
  * TraceConfig Instrumentation does not extend Default.
  *
@@ -42,16 +42,29 @@ public class TraceConfigInstrumentation implements Instrumenter {
           + PACKAGE_CLASS_NAME_REGEX
           + "\\["
           + METHOD_LIST_REGEX
-          + "\\]\\s*;?\\s*";
+          + "\\]";
 
   private final Map<String, Set<String>> classMethodsToTrace;
 
+  private boolean validateConfigString(String configString) {
+    for (String clazz : configString.split(";")) {
+      if (!clazz.matches(CONFIG_FORMAT)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
   public TraceConfigInstrumentation() {
-    final String configString = Config.get().getTraceMethods();
+    this(Config.get().getTraceMethods());
+  }
+
+  public TraceConfigInstrumentation(final String configString) {
+
     if (configString == null || configString.trim().isEmpty()) {
       classMethodsToTrace = Collections.emptyMap();
 
-    } else if (!configString.matches(CONFIG_FORMAT)) {
+    } else if (!validateConfigString(configString)) {
       log.warn(
           "Invalid trace method config '{}'. Must match 'package.Class$Name[method1,method2];*'.",
           configString);