[SPARK-16800][EXAMPLES][ML] Fix Java examples that fail to run due to exception

## What changes were proposed in this pull request?
Some Java examples are using mllib.linalg.Vectors instead of ml.linalg.Vectors and causes an exception when run.  Also there are some Java examples that incorrectly specify data types in the schema, also causing an exception.

## How was this patch tested?
Ran corrected examples locally

Author: Bryan Cutler <cutlerb@gmail.com>

Closes #14405 from BryanCutler/java-examples-ml.Vectors-fix-SPARK-16800.