Guava java EventBus实例化错误

Question

I'm trying to use EventBus of Google's Guava libraries.

From Guava's documentation it should be easy to instantiate an EventBus object.

My code:

package test;

import com.google.common.eventbus.EventBus;

public class Test {
    public static void main(String[] args) {
        EventBus bus = new EventBus("Sample");
    }
}

I'm getting this error:

Exception in thread "main" java.lang.NoSuchMethodError: com.google.common.base.Objects.firstNonNull(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
at com.google.common.cache.CacheBuilder.getKeyStrength(CacheBuilder.java:355)
at com.google.common.cache.CustomConcurrentHashMap.<init>(CustomConcurrentHashMap.java:206)
at com.google.common.cache.ComputingCache.<init>(ComputingCache.java:39)
at com.google.common.cache.CacheBuilder.build(CacheBuilder.java:569)
at com.google.common.eventbus.EventBus.<init>(EventBus.java:156)
at test.Test.main(Test.java:7)
Java Result: 1

I've tried with Guava 10.0, 11.0 and 12.0 and always the same error. I'm on OSX Lion and I'm using Netbeans 7.1: I've tried both Java 6 (32 and 64bit) and Java 7: no improvements. On google i can't find anything. Is it a problem with Guava? Or, as usually, am I missing something?

Best regards,

Alessandro

Answer 1

To expand on what @biziclop said, you most likely have both a recent version of Guava and either google-collect or a version of Guava prior to 3.0 on your classpath. Objects.firstNonNull was added in 3.0, suggesting that an old version of that class is being loaded.

Answer 2

I had the same problem. I was using google-collections 1.0 where guava is v11. This problem went away after I upgraded to

<!-- https://mvnrepository.com/artifact/com.google.guava/guava --> <dependency> <groupId>com.google.guava</groupId> <artifactId>guava</artifactId> <version>19.0</version> </dependency> from

<dependency>
  <groupId>com.google.collections</groupId>
  <artifactId>google-collections</artifactId>
  <version>1.0</version>
</dependency>