diff --git a/bundler-maven-plugin/src/main/java/de/saumya/mojo/bundler/InstallMojo.java b/bundler-maven-plugin/src/main/java/de/saumya/mojo/bundler/InstallMojo.java
index c46bf397..9e1b1054 100644
--- a/bundler-maven-plugin/src/main/java/de/saumya/mojo/bundler/InstallMojo.java
+++ b/bundler-maven-plugin/src/main/java/de/saumya/mojo/bundler/InstallMojo.java
@@ -327,7 +327,7 @@ public String toString(){
         }
     private void getHistoryLogScript(RubyStringBuilder builder) {
         builder.appendLine("log = File.join('log', 'history.log')");
-        builder.appendLine("if File.exists? File.dirname(log)");
+        builder.appendLine("if File.exist? File.dirname(log)");
         builder.appendLine("  File.open(log, 'a') do |f|");
         builder.appendLine("    f.puts \"#{$0.sub(/.*\\//, '')} #{ARGV.join ' '}\"");
         builder.appendLine("  end");
diff --git a/gem-assembly-descriptors/src/it/assemble-project-with-gems/application/pom.xml b/gem-assembly-descriptors/src/it/assemble-project-with-gems/application/pom.xml
index ff656785..e3e8fa8c 100644
--- a/gem-assembly-descriptors/src/it/assemble-project-with-gems/application/pom.xml
+++ b/gem-assembly-descriptors/src/it/assemble-project-with-gems/application/pom.xml
@@ -56,7 +56,7 @@
       </plugin>   
       <plugin>
 	<artifactId>maven-assembly-plugin</artifactId>
-	<version>2.2-beta-5</version>
+	<version>3.7.1</version>
 	<configuration>
 	  <descriptorRefs>
 	    <descriptorRef>jar-with-dependencies-and-gems</descriptorRef>
@@ -71,7 +71,7 @@
 	  <execution>
 	    <phase>package</phase>
 	    <goals>
-	      <goal>assembly</goal>
+	      <goal>single</goal>
 	    </goals>
 	  </execution>
 	</executions>
diff --git a/gem-assembly-descriptors/src/it/assemble-project-without-gems/application/pom.xml b/gem-assembly-descriptors/src/it/assemble-project-without-gems/application/pom.xml
index db9be552..ca8a8e3f 100644
--- a/gem-assembly-descriptors/src/it/assemble-project-without-gems/application/pom.xml
+++ b/gem-assembly-descriptors/src/it/assemble-project-without-gems/application/pom.xml
@@ -43,8 +43,8 @@
 	<artifactId>maven-compiler-plugin</artifactId>
 	<version>3.1</version>
 	<configuration>
-	  <source>1.6</source>
-	  <target>1.6</target>
+	  <source>8</source>
+	  <target>8</target>
 	</configuration>
       </plugin>
       <plugin>
diff --git a/gem-assembly-descriptors/src/it/assemble-project-without-gems/java-world/pom.xml b/gem-assembly-descriptors/src/it/assemble-project-without-gems/java-world/pom.xml
index 5b2420f6..82403976 100644
--- a/gem-assembly-descriptors/src/it/assemble-project-without-gems/java-world/pom.xml
+++ b/gem-assembly-descriptors/src/it/assemble-project-without-gems/java-world/pom.xml
@@ -12,8 +12,8 @@
 	<artifactId>maven-compiler-plugin</artifactId>
 	<version>3.1</version>
 	<configuration>
-	  <source>1.6</source>
-	  <target>1.6</target>
+	  <source>8</source>
+	  <target>8</target>
 	</configuration>
       </plugin>
     </plugins>
diff --git a/gem-maven-plugin/src/it/gemify-pom/pom.xml b/gem-maven-plugin/src/it/gemify-pom/pom.xml
index d4e27abf..d7da80b3 100644
--- a/gem-maven-plugin/src/it/gemify-pom/pom.xml
+++ b/gem-maven-plugin/src/it/gemify-pom/pom.xml
@@ -25,6 +25,10 @@
       <plugin>
         <artifactId>maven-compiler-plugin</artifactId>
         <version>3.8.1</version>
+        <configuration>
+          <source>8</source>
+          <target>8</target>
+        </configuration>
       </plugin>
     </plugins>
   </build>
diff --git a/gem-maven-plugin/src/it/include-rubygems-in-resources/pom.xml b/gem-maven-plugin/src/it/include-rubygems-in-resources/pom.xml
index 92be80d1..79113a5b 100644
--- a/gem-maven-plugin/src/it/include-rubygems-in-resources/pom.xml
+++ b/gem-maven-plugin/src/it/include-rubygems-in-resources/pom.xml
@@ -80,6 +80,10 @@
             <plugin>
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.8.1</version>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                </configuration>
             </plugin>
         </plugins>
     </build>
diff --git a/gem-maven-plugin/src/it/include-rubygems-in-test-resources/pom.xml b/gem-maven-plugin/src/it/include-rubygems-in-test-resources/pom.xml
index 8476008e..f2d347b2 100644
--- a/gem-maven-plugin/src/it/include-rubygems-in-test-resources/pom.xml
+++ b/gem-maven-plugin/src/it/include-rubygems-in-test-resources/pom.xml
@@ -60,8 +60,8 @@
 	<artifactId>maven-compiler-plugin</artifactId>
 	<version>3.1</version>
 	<configuration>
-	  <target>1.6</target>
-	  <source>1.6</source>
+	  <target>8</target>
+	  <source>8</source>
 	</configuration>
       </plugin>
       <plugin>
diff --git a/gem-maven-plugin/src/it/small-project/java-world/pom.xml b/gem-maven-plugin/src/it/small-project/java-world/pom.xml
index 05c9578f..4405d738 100644
--- a/gem-maven-plugin/src/it/small-project/java-world/pom.xml
+++ b/gem-maven-plugin/src/it/small-project/java-world/pom.xml
@@ -11,6 +11,10 @@
       <plugin>
         <artifactId>maven-compiler-plugin</artifactId>
         <version>3.8.1</version>
+        <configuration>
+          <source>8</source>
+          <target>8</target>
+        </configuration>
       </plugin>
     </plugins>
   </build>
diff --git a/gem-maven-plugin/src/main/java/de/saumya/mojo/gem/PackageMojo.java b/gem-maven-plugin/src/main/java/de/saumya/mojo/gem/PackageMojo.java
index 31ef7dca..b20bf84d 100644
--- a/gem-maven-plugin/src/main/java/de/saumya/mojo/gem/PackageMojo.java
+++ b/gem-maven-plugin/src/main/java/de/saumya/mojo/gem/PackageMojo.java
@@ -370,7 +370,7 @@ else if ((Artifact.SCOPE_PROVIDED + Artifact.SCOPE_TEST).contains(dependency.get
                 writer.append("end\n");
                 writer.append("\n");
                 writer.append("load File.dirname(__FILE__) + '/" + this.gemHook
-                        + "' if File.exists?( File.dirname(__FILE__) + '/"
+                        + "' if File.exist?( File.dirname(__FILE__) + '/"
                         + this.gemHook + "')\n");
             }
             catch (final IOException e) {
diff --git a/parent-mojo/pom.xml b/parent-mojo/pom.xml
index 2be30a77..f1144100 100644
--- a/parent-mojo/pom.xml
+++ b/parent-mojo/pom.xml
@@ -50,7 +50,7 @@
     <plugins>
       <plugin>
         <artifactId>maven-source-plugin</artifactId>
-        <version>2.4</version>
+        <version>3.2.1</version>
         <executions>
           <execution>
             <goals><goal>jar</goal></goals>
diff --git a/pom.xml b/pom.xml
index 8fb98576..31097bd5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -140,7 +140,7 @@
         </plugin>
         <plugin>
           <artifactId>maven-jar-plugin</artifactId>
-          <version>2.3</version>
+          <version>3.4.1</version>
         </plugin>
         <plugin>
           <artifactId>maven-dependency-plugin</artifactId>
diff --git a/ruby-tools/src/main/scripts/install_gems.rb b/ruby-tools/src/main/scripts/install_gems.rb
index 9bfb64bb..b654f527 100644
--- a/ruby-tools/src/main/scripts/install_gems.rb
+++ b/ruby-tools/src/main/scripts/install_gems.rb
@@ -10,7 +10,7 @@
 
 Dir[ 'target/dependency/*gem' ].each do |file|
   f = "../target/rubygems/gems/#{File.basename(file).sub(/.gem/, '')}/lib"
-  unless File.exists?( f )
+  unless File.exist?( f )
     f = "../target/rubygems/gems/#{File.basename(file).sub(/.gem/, '')}-java/lib"
   end
   Dir[ File.expand_path( f ) + "/*" ].each do |ff|
diff --git a/ruby-tools/src/test/resources/repository/org/apache/ant/ant-launcher/1.7.1/ant-launcher-1.7.1.pom b/ruby-tools/src/test/resources/repository/org/apache/ant/ant-launcher/1.7.1/ant-launcher-1.7.1.pom
index 49b985aa..5f6d27f6 100644
--- a/ruby-tools/src/test/resources/repository/org/apache/ant/ant-launcher/1.7.1/ant-launcher-1.7.1.pom
+++ b/ruby-tools/src/test/resources/repository/org/apache/ant/ant-launcher/1.7.1/ant-launcher-1.7.1.pom
@@ -39,8 +39,8 @@
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-compiler-plugin</artifactId>
         <configuration>
-          <source>1.2</source>
-          <target>1.2</target>
+          <source>8</source>
+          <target>8</target>
           <includes>
             <include>org/apache/tools/ant/launch/*.java</include>
           </includes>
diff --git a/ruby-tools/src/test/resources/repository/org/apache/ant/ant/1.7.1/ant-1.7.1.pom b/ruby-tools/src/test/resources/repository/org/apache/ant/ant/1.7.1/ant-1.7.1.pom
index 52e59f00..df1b39eb 100644
--- a/ruby-tools/src/test/resources/repository/org/apache/ant/ant/1.7.1/ant-1.7.1.pom
+++ b/ruby-tools/src/test/resources/repository/org/apache/ant/ant/1.7.1/ant-1.7.1.pom
@@ -111,8 +111,8 @@
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-compiler-plugin</artifactId>
         <configuration>
-          <source>1.2</source>
-          <target>1.2</target>
+          <source>8</source>
+          <target>8</target>
           <excludes>
             <exclude>org/apache/tools/ant/taskdefs/optional/**</exclude>
             <exclude>org/apache/tools/ant/filters/util/JavaClassHelper*</exclude>