7176907: additional warnings cleanup in java.util, java.util.regexp, java.util.zip

Reviewed-by: forax, khazra, smarks
Contributed-by: NMani Sarkar <sadhak001@gmail.com>

src/share/classes/java/util/InvalidPropertiesFormatException.java

@@ -44,6 +44,9 @@ import java.io.IOException;
  */
 
 public class InvalidPropertiesFormatException extends IOException {
+
+    private static final long serialVersionUID = 7763056076009360219L;
+
     /**
      * Constructs an InvalidPropertiesFormatException with the specified
      * cause.

src/share/classes/java/util/regex/Pattern.java

@@ -2026,6 +2026,7 @@ loop:   for(int x=0, offset=0; x<nCodePoints; x++, offset+=len) {
         }
     }
 
+    @SuppressWarnings("fallthrough")
     /**
      * Parsing of sequences between alternations.
      */
@@ -2140,6 +2141,7 @@ loop:   for(int x=0, offset=0; x<nCodePoints; x++, offset+=len) {
         return head;
     }
 
+    @SuppressWarnings("fallthrough")
     /**
      * Parse and add a new Single or Slice.
      */
@@ -2978,6 +2980,7 @@ loop:   for(int x=0, offset=0; x<nCodePoints; x++, offset+=len) {
         return head;
     }
 
+    @SuppressWarnings("fallthrough")
     /**
      * Parses inlined match flags and set them appropriately.
      */
@@ -3019,6 +3022,7 @@ loop:   for(int x=0, offset=0; x<nCodePoints; x++, offset+=len) {
         }
     }
 
+    @SuppressWarnings("fallthrough")
     /**
      * Parses the second part of inlined match flags and turns off
      * flags appropriately.

src/share/classes/java/util/zip/GZIPInputStream.java

@@ -252,7 +252,7 @@ class GZIPInputStream extends InflaterInputStream {
      */
     private int readUShort(InputStream in) throws IOException {
         int b = readUByte(in);
-        return ((int)readUByte(in) << 8) | b;
+        return (readUByte(in) << 8) | b;
     }
 
     /*