diff --git a/How-to-build-ANTLR-itself.md b/How-to-build-ANTLR-itself.md
index ce2fd8b..c536808 100644
--- a/How-to-build-ANTLR-itself.md
+++ b/How-to-build-ANTLR-itself.md
@@ -77,6 +77,12 @@ Take a look in the bild.log file that is always produced if you'd like to see pr
 ...
 ```
 
+BTW, if you get an error about `Picked up JAVA_TOOL_OPTIONS: -javaagent:/usr/share/java/jayatanaag.jar` see [stackoverflow solution](http://stackoverflow.com/questions/26074446/picked-up-java-tool-options-javaagent-usr-share-java-jayatanaag-jar-when-st). Just:
+
+```bash
+$ unset JAVA_TOOL_OPTIONS
+```
+
 You will also notice that the build script has pulled in the necessary jars, sort of like maven would:
 
 ```bash