This is an easy to use disk cache which uses DiskLruCache under the hood. The DiskLruCache is nice, but it has too low level interface for most use cases.
Reservoir is a simple library for Android that allows you to easily serialize and cache your objects to disk using key/value pairs.
The HttpResponseCache library provides transparent and automatic caching of HTTP and HTTPS requests that use the java.net.HttpUrlConnection classes.
For information on how to use HttpUrlConnection, refer to the Android documentation - don't worry, the information also applies to non-Android Java.
Java implementation of a Disk-based LRU cache which specifically targets Android compatibility.
A simple in memory and persistent Object cache for Android.
An image download-and-cacher that also knows how to efficiently generate and retrieve thumbnails of various sizes.