Fix: log4j example: set logger level to prevent unexpected level inheritance

[lttng-ust.git] / doc / examples / java-log4j / Hello.java

diff --git a/doc/examples/java-log4j/Hello.java b/doc/examples/java-log4j/Hello.java
index a477e334604e2732555222de7ed8452785e07cee..2f1119c05e346d85d9da45f5650d1d355bf5cf24 100644 (file)
--- a/doc/examples/java-log4j/Hello.java
+++ b/doc/examples/java-log4j/Hello.java
@@ -26,6 +26,7 @@ import java.io.IOException;
 import org.apache.log4j.Appender;
 import org.apache.log4j.BasicConfigurator;
 import org.apache.log4j.Logger;
+import org.apache.log4j.Level;
 import org.lttng.ust.agent.log4j.LttngLogAppender;
 
 /**
@@ -64,6 +65,17 @@ public class Hello {
         *             command line.
         */
        public static void main(String args[]) throws IOException {
+
+               /*
+                * Set lowest level to make sure all event levels are logged.
+                * Any jar can override the default log4j rootLogger level
+                * and a logger with no explicit level defaults to the non-null
+                * parent level. Events could be ignored if the inherited value
+                * is to low.
+                * e.g BSF  -> https://issues.apache.org/jira/browse/BSF-24
+                */
+               HELLO_LOG.setLevel(Level.ALL);
+
                /* Start with the default Log4j configuration, which logs to console */
                BasicConfigurator.configure();