Added 14 solutions

Java/Strings/Pattern Syntax Checker/Solution.java

@@ -0,0 +1,23 @@
+import java.util.Scanner;
+import java.util.regex.Pattern;
+import java.util.regex.PatternSyntaxException;
+
+/* If a PatternSyntaxException is not thrown by Pattern.compile,
+   then the regular expression is valid.
+*/
+public class Solution {
+    public static void main(String[] args){
+        Scanner scan = new Scanner(System.in);
+        int testCases = Integer.parseInt(scan.nextLine());
+        while (testCases > 0){
+           String pattern = scan.nextLine();
+           try {
+               Pattern.compile(pattern);
+               System.out.println("Valid");
+           } catch (PatternSyntaxException exception) {
+               System.out.println("Invalid");
+           }
+        }
+        scan.close();
+    }
+}