You could also try retargeting the animations in Blender, since it looks like you have the animation files in .gltf format.
Blender should allow you to import the gltf files, merge the animations, and then export a single gltf file that contains multiple animations.
Walk.scale(50f);
在我把武器绑定到手骨骼的时候我也发现武器会变小但是我添加model.scale(50f); 把武器调整到了正常尺寸
But the animation didn’t work and I changed the value and it didn’t show correctly
Yes, that’s a good way to do it but I’m going to get a lot of animation files from different people and I’m going to try to use JME’s internal functionality to combine animation files from different files that are all from the same skeleton
Ali_RS It gives me a really nice hint that animations can be combined
But there’s something wrong with it 
Maybe it’s a local scale problem, but I tried “walk.scale (50f);” The model didn’t live up to expectations
When I tried to simply apply the animation from one armature to the other one from the Blender Action Editor the result looked wrong. I see that their Rest pose is slightly different this could be the reason why the animation did not show up right.
Then I tried to remap it using Auto Rig Pro addon (it is a commercial addon that also has a remap tool that can be used to remap animation from one armature to another even if they have different bone names and rest pose) and it worked fine. (See retargeting using Auto Rig Pro video tutorials)
The next issue was that the armature scale was not 1. You need to apply the scale and rotation of objects in the blender before exporting to JME. (Ctr+A → Apply Rotation & Scale) but must do this before animating the character, doing this after, will ruin the animations so what I did was that I duplicated the character and removed all the animations from it and then applied the rotation and scale on armature and body parts, then using the Auto Rig Pro addon I remapped the animations from original character to the new one and done!
You can get the blender file and the exported gltf file from this link. The character has two animations on it “Stand” and “Walk”. I have not tested it on JME, I leave this to you to test it on JME. 
Edit:
But regarding the Wes library retargetAnimation not sure why the model shrinks after retargeting.
My model animation is back to normal.
It can be confirmed that there is something wrong with my file. Everything is normal with my code using the file you uploaded.
Thank you for your help these days
