Apparently it doesn't work like that

.travis.yml

@@ -2,10 +2,9 @@ cache:
   directories:
   - $HOME/.m2/repository/org/bukkit/craftbukkit
 before_install: # Wget BuildTools and run if cached folder not found
-  - if [ ! -d "$HOME/.m2/repository/org/bukkit/craftbukkit" ]; then
+  - if [ -d "$HOME/.m2/repository/org/bukkit/craftbukkit" ]; then exit 0; fi
   - wget -O BuildTools.jar https://hub.spigotmc.org/jenkins/job/BuildTools/lastSuccessfulBuild/artifact/target/BuildTools.jar
   - java -jar BuildTools.jar
-  - fi
 
 language: java
 jdk: