build: enable failOnWarning (#433)

Author: c-dilks

pom.xml

@@ -69,6 +69,7 @@
         <configuration>
           <release>21</release>
           <compilerId>groovy-eclipse-compiler</compilerId>
+          <failOnWarning>true</failOnWarning>
         </configuration>
         <dependencies>
           <!-- https://groovy.jfrog.io/ui/native/plugins-release/org/codehaus/groovy/groovy-eclipse-compiler/ -->

src/main/java/org/jlab/clas/timeline/histograms/ALERT.java

@@ -80,13 +80,11 @@ public ALERT(int reqrunNum, String reqOutputDir, float reqEb, boolean reqTimeBas
     AHDC_TIME     = new H1F[576];
 
     for (int index = 0; index<576; index++) {
-      int layer = 0;
       int layer_number = 0;
       int wire_number = 0;
 
       for (int j=0; j<8; j++){
         if (index < layer_wires_cumulative[j+1]){
-          layer = layer_encoding[j];
           layer_number = j + 1;
           wire_number = index + 1 - layer_wires_cumulative[j];
           break;