Definitely, yes. In the Mahout Recommender First-Timer FAQ they advise against starting out with a Hadoop-based implementation (unless you know you're going to be scaling past 100 million user preferences relatively quickly).
You can use the implementations of the Recommender interface in a pure-Java fashion relatively easily. Or place one in the servlet of your choice.
Technically, Mahout has a Maven dependency on Hadoop. But you can use recommenders without the Hadoop JARs easily. This is described in the first few chapters of Mahout in Action - you can download the sample source code and see how it's done - look at the file RecommenderIntro.java
.
However, if you're using Maven, you would need to exclude Hadoop manually - the dependency would look like this:
<dependency>
<groupId>org.apache.mahout</groupId>
<artifactId>mahout-core</artifactId>
<exclusions>
<exclusion>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-core</artifactId>
</exclusion>
</exclusions>
</dependency>