I have achieved it!
I follow this other topic where there is explain how to initialize the variable list.
This is my code now:
Variable = jpy.get_type('org.esa.snap.core.gpf.common.MosaicOp$Variable')
variables = jpy.array('org.esa.snap.core.gpf.common.MosaicOp$Variable', 13)
variables[0] = Variable('B1', 'B1')
variables[1] = Variable('B2', 'B2')
variables[2] = Variable('B3', 'B3')
variables[3] = Variable('B4', 'B4')
variables[4] = Variable('B5', 'B5')
variables[5] = Variable('B6', 'B6')
variables[6] = Variable('B7', 'B7')
variables[7] = Variable('B8', 'B8')
variables[8] = Variable('B8A', 'B8A')
variables[9] = Variable('B9', 'B9')
variables[10] = Variable('B10', 'B10')
variables[11] = Variable('B11', 'B11')
variables[12] = Variable('B12', 'B12')
...
MosaicOp = esa_snappy.jpy.get_type('org.esa.snap.core.gpf.common.MosaicOp')
mosOp = MosaicOp()
mosOp.setSourceProducts(products)
mosOp.setParameterDefaultValues()
mosOp.setParameter('variables', variables)
mosOp.setParameter('westBound','116.99984025621173')
mosOp.setParameter('northBound','32.53731013088188')
mosOp.setParameter('eastBound','118.16895344915102')
mosOp.setParameter('southBound','30.639816504441374')
mosaickImage = mosOp.getTargetProduct()
And the process ends succesfully.
I still interested on the call gpt from Python thing that you commented before.
If you can explain it to me, I’ll be so grateful.
Thanks!
Álvaro