Consistent SpotBugs configuration & warning fixes.

build.gradle

@@ -1,38 +1,43 @@
-allprojects {
-    apply plugin: 'findbugs'
-
-    group = 'com.lyndir.masterpassword'
-    version = '2.7.10'
-
-    tasks.withType( JavaCompile ) {
-        options.encoding = 'UTF-8'
-        sourceCompatibility = '1.8'
-        targetCompatibility = '1.8'
-    }
-    tasks.withType( FindBugs ) {
-        reports {
-            xml.enabled = false
-            html.enabled = true
-        }
-    }
-}
-
 buildscript {
     repositories {
         google()
         jcenter()
+        gradlePluginPortal()
     }
 
     dependencies {
         classpath group: 'com.android.tools.build', name: 'gradle', version: '3.5.0'
+        classpath group: 'gradle.plugin.com.github.spotbugs', name: 'spotbugs-gradle-plugin', version: '2.0.0'
     }
 }
 
+allprojects {
+    group = 'com.lyndir.masterpassword'
+    version = '2.7.10'
+}
+
 subprojects {
+    apply plugin: 'com.github.spotbugs'
+
     repositories {
         google()
         jcenter()
         mavenCentral()
         maven { url 'https://maven.lyndir.com' }
     }
+    dependencies {
+        spotbugsPlugins group: 'com.h3xstream.findsecbugs', name: 'findsecbugs-plugin', version: '1.9.0'
+    }
+
+    tasks.withType( JavaCompile ) {
+        options.encoding = 'UTF-8'
+        sourceCompatibility = '1.8'
+        targetCompatibility = '1.8'
+    }
+    tasks.withType( com.github.spotbugs.SpotBugsTask ) {
+        reports {
+            xml.enabled = false
+            html.enabled = true
+        }
+    }
 }