Question

1. I will go over to Japan. [Will is stressed in this sentence.]

2. I will go over to Japan. [Will is not stressed in this sentence.]
3. I'll go over to Japan. [We can see a contracted form, "I'll" here.]
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Do we have any differences in meaning because of the state of 'will'?

Answer 1

I'm not sure what you're asking. If "will" is stressed, it indicates some determination, perhaps overcoming some obstacle to the trip. If it's not stressed, contracted or not, it's merely a statement of the speaker's intention to make the trip to Japan.