Polish & Clean up code

doc/installation.md

@@ -36,7 +36,7 @@ You can override any configuration values with `-D` option.
 To change the http(default 8080) and grpc(default 8080) ports used by Collector, you can change the settings below.
  - `-Darmeria.port`: http, grpc uses 8080 by default
 
-To change the default value of 10MB for the max message size of gRPC in Collector, change the setting below.
+To change the the max message size of gRPC in Collector, change the setting below.
  - `-Darmeria.max-message-size`: 10MB by default
     - Supports `B`, `KB`, `MB`, `GB`, and `TB` units.
 
@@ -178,10 +178,10 @@ packages=com.navercorp
 
 - Setting up the agent via `-javaagent:path/to/scavenger-agent.jar`
 - Specify the config file via `-Dscavenger.configuration=path/to/scavenger.conf`
-- To change the default value of 10MB for the max message size of gRPC in agent, change the setting below.
+- To change the max message size of gRPC in agent, change the setting below.
 - `-Dscavenger.max-message-size`
     - Supports `B`, `KB`, `MB`, `GB`, and `TB` units.
-> **We recommend tuning your codeBase configuration before changing `scavenger.max-message-size`.**
+> **We recommend tuning your codeBase configuration for minimizing tracing ranges before changing `scavenger.max-message-size`.**
 
 ```bash
 export JAVA_OPTS="$JAVA_OPTS -Dscavenger.configuration=$CATALINA_BASE/conf/scavenger.conf"

scavenger-agent-java/src/main/java/com/navercorp/scavenger/javaagent/publishing/GrpcClient.java

@@ -98,6 +98,10 @@ private ManagedChannel createChannel(int maxMessageSize) {
 
     private int maxMessageSize() {
         String mexMessageSize = System.getProperty(MAX_MESSAGE_SIZE_CONFIG);
+        if (mexMessageSize == null) {
+            return DEFAULT_MAX_MESSAGE_SIZE;
+        }
+
         Matcher matcher = DATA_SIZE_PATTERN.matcher(mexMessageSize);
         if (!matcher.matches()) {
             log.log(Level.WARNING, "[scavenger] 'scavenger.max-message-size' is not a valid data size. use the default value of 10MB");