I've added following dependency

	<dependency>
		<groupId>com.google.cloud</groupId>
		<artifactId>google-cloud-pubsub</artifactId>
		<version>0.6.0</version>
	</dependency>
	<dependency>
		<groupId>com.google.auth</groupId>
		<artifactId>google-auth-library-oauth2-http</artifactId>
		<version>0.6.0</version>
	</dependency>
	<dependency>
		<groupId>com.google.appengine</groupId>
		<artifactId>appengine-api-1.0-sdk</artifactId>
		<version>1.9.48</version>
	</dependency>
	<dependency>
		<groupId>com.google.cloud</groupId>
		<artifactId>google-cloud-nio</artifactId>
		<version>0.6.0</version>
    </dependency>

Below is the code snippet

PubSub buildPubSub(String appName){
    PubSubOptions.Builder optionsBuilder = PubSubOptions.newBuilder();
    return optionsBuilder.setProjectId(appName).build().getService();
}

I keep on getting below error

Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.google.cloud.pubsub.PubSub]: Factory method 'pubSub' threw exception; nested exception is java.lang.NoClassDefFoundError: io/netty/handler/codec/Headers
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:189) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:588) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
... 104 common frames omitted
Caused by: java.lang.NoClassDefFoundError: io/netty/handler/codec/Headers
at java.lang.ClassLoader.defineClass1(Native Method) ~[na:1.8.0_45]
at java.lang.ClassLoader.defineClass(ClassLoader.java:760) ~[na:1.8.0_45]
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) ~[na:1.8.0_45]
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467) ~[na:1.8.0_45]
at java.net.URLClassLoader.access$100(URLClassLoader.java:73) ~[na:1.8.0_45]
at java.net.URLClassLoader$1.run(URLClassLoader.java:368) ~[na:1.8.0_45]
at java.net.URLClassLoader$1.run(URLClassLoader.java:362) ~[na:1.8.0_45]
at java.security.AccessController.doPrivileged(Native Method) ~[na:1.8.0_45]
at java.net.URLClassLoader.findClass(URLClassLoader.java:361) ~[na:1.8.0_45]
at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_45]
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) ~[na:1.8.0_45]
at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_45]
at io.grpc.netty.NettyChannelBuilder$NettyTransportFactory.(NettyChannelBuilder.java:311) ~[grpc-netty-1.0.1.jar:1.0.1]
at io.grpc.netty.NettyChannelBuilder$NettyTransportFactory.(NettyChannelBuilder.java:280) ~[grpc-netty-1.0.1.jar:1.0.1]
at io.grpc.netty.NettyChannelBuilder.buildTransportFactory(NettyChannelBuilder.java:230) ~[grpc-netty-1.0.1.jar:1.0.1]
at io.grpc.internal.AbstractManagedChannelImplBuilder.build(AbstractManagedChannelImplBuilder.java:239) ~[grpc-core-1.0.1.jar:1.0.1]
at com.google.api.gax.grpc.InstantiatingChannelProvider.createChannel(InstantiatingChannelProvider.java:120) ~[gax-0.0.22.jar:na]
at com.google.api.gax.grpc.InstantiatingChannelProvider.getChannel(InstantiatingChannelProvider.java:107) ~[gax-0.0.22.jar:na]
at com.google.api.gax.grpc.ProviderManager.getChannel(ProviderManager.java:107) ~[gax-0.0.22.jar:na]
at com.google.api.gax.grpc.ChannelAndExecutor.create(ChannelAndExecutor.java:68) ~[gax-0.0.22.jar:na]
at com.google.api.gax.grpc.ServiceApiSettings.getChannelAndExecutor(ServiceApiSettings.java:82) ~[gax-0.0.22.jar:na]
at com.google.cloud.pubsub.spi.v1.PublisherApi.(PublisherApi.java:203) ~[google-cloud-pubsub-0.6.0.jar:0.6.0]
at com.google.cloud.pubsub.spi.v1.PublisherApi.create(PublisherApi.java:194) ~[google-cloud-pubsub-0.6.0.jar:0.6.0]
at com.google.cloud.pubsub.spi.DefaultPubSubRpc.(DefaultPubSubRpc.java:168) ~[google-cloud-pubsub-0.6.0.jar:0.6.0]
at com.google.cloud.pubsub.PubSubOptions$DefaultPubSubRpcFactory.create(PubSubOptions.java:69) ~[google-cloud-pubsub-0.6.0.jar:0.6.0]
at com.google.cloud.pubsub.PubSubOptions$DefaultPubSubRpcFactory.create(PubSubOptions.java:63) ~[google-cloud-pubsub-0.6.0.jar:0.6.0]
at com.google.cloud.ServiceOptions.getRpc(ServiceOptions.java:478) ~[google-cloud-core-0.6.0.jar:0.6.0]
at com.google.cloud.pubsub.PubSubImpl.(PubSubImpl.java:115) ~[google-cloud-pubsub-0.6.0.jar:0.6.0]
at com.google.cloud.pubsub.PubSubOptions$DefaultPubSubFactory.create(PubSubOptions.java:44) ~[google-cloud-pubsub-0.6.0.jar:0.6.0]
at com.google.cloud.pubsub.PubSubOptions$DefaultPubSubFactory.create(PubSubOptions.java:39) ~[google-cloud-pubsub-0.6.0.jar:0.6.0]
at com.google.cloud.ServiceOptions.getService(ServiceOptions.java:465) ~[google-cloud-core-0.6.0.jar:0.6.0]
at com.homedepot.checkout.pubsub.PubSubAdapter.buildPubSub(PubSubAdapter.java:83) ~[classes/:na]
at com.homedepot.checkout.pubsub.PubSubConfiguration.pubSub(PubSubConfiguration.java:69) ~[classes/:na]
at com.homedepot.checkout.pubsub.PubSubConfiguration$$EnhancerBySpringCGLIB$$2a49f60b.CGLIB$pubSub$1() ~[classes/:na]
at com.homedepot.checkout.pubsub.PubSubConfiguration$$EnhancerBySpringCGLIB$$2a49f60b$$FastClassBySpringCGLIB$$b610cce5.invoke() ~[classes/:na]
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228) ~[spring-core-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:355) ~[spring-context-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at com.homedepot.checkout.pubsub.PubSubConfiguration$$EnhancerBySpringCGLIB$$2a49f60b.pubSub() ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_45]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_45]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_45]
at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_45]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:162) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
... 105 common frames omitted
Caused by: java.lang.ClassNotFoundException: io.netty.handler.codec.Headers
at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[na:1.8.0_45]
at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_45]
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) ~[na:1.8.0_45]
at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_45]
... 148 common frames omitted

Any help would be appreciated.

Thanks
MV