I am a beginner in Jcuda. Also. I am a PhD student, building a project with Jcuda. I need a project dedicated for shared memory in order to learn how to use it.
Hello, i think, Marco13 will soon help you with any clues and suggestions, in the interim please stand-by. 
There is an example in the jcuda-samples project, consisting of
- the main file: https://github.com/jcuda/jcuda-samples/blob/master/JCudaSamples/src/main/java/jcuda/driver/samples/JCudaReduction.java
- the kernel: https://github.com/jcuda/jcuda-samples/blob/master/JCudaSamples/src/main/resources/kernels/JCudaReductionKernel.cu
It is basically a port of the CUDA reduction sample, which shows some basic optimization techniques, including the use of __shared__ memory. The example is described in more detail in this PDF file: https://developer.download.nvidia.com/assets/cuda/files/reduction.pdf
Thanks a lot