Merge various cleanup java test, test files, comments (#1364)

Plus some spelling corrections

java/examples/datasets/H5Ex_D_UnlimitedMod.java

@@ -17,7 +17,7 @@
   file.  Next, it reopens the file, reads back the data,
   outputs it to the screen, extends the dataset, and writes
   new data to the entire extended dataset.  Finally it
-  reopens the file again, reads back the data, and utputs it
+  reopens the file again, reads back the data, and outputs it
   to the screen.
  ************************************************************/
 package examples.datasets;