finally managed findbugs 3.0 and jdk 1.8 upgrade (had to use hard-coded

asciidoctor version)

build.gradle

@@ -18,10 +18,8 @@ import org.apache.tools.ant.filters.ReplaceTokens
 
 group = 'at.uibk.dbis'
 version = '0.3.3-SNAPSHOT'
-sourceCompatibility=JavaVersion.VERSION_1_7
-targetCompatibility=JavaVersion.VERSION_1_7
-//sourceCompatibility=JavaVersion.VERSION_1_8
-//targetCompatibility=JavaVersion.VERSION_1_8
+sourceCompatibility=JavaVersion.VERSION_1_8
+targetCompatibility=JavaVersion.VERSION_1_8
 
 description = 'PhD project of Nikolaus Krismer'
 
@@ -49,7 +47,7 @@ description = 'PhD project of Nikolaus Krismer'
 
 ext {
 	isRelease = false
-	versionFindbugs = '2.0.3'
+	versionFindbugs = '+'
 	versionJacoco = '+'
 }
 
@@ -124,7 +122,8 @@ buildscript {
 
 	dependencies {
 		classpath 'org.gradle.api.plugins:gradle-vagrant-plugin:+'
-		classpath 'org.asciidoctor:asciidoctor-gradle-plugin:+'
+		// hard-coded asciidoctor plugin version... for more detail see: https://github.com/asciidoctor/asciidoctor-gradle-plugin/issues/84
+		classpath 'org.asciidoctor:asciidoctor-gradle-plugin:0.7.1'
 	}
 }
 
@@ -208,7 +207,7 @@ eclipse {
 
 findbugs {
 //	effort = 'max'
-	ignoreFailures = true
+//	ignoreFailures = true
 //	reportLevel = 'low'
 	toolVersion = versionFindbugs
 }