Using "Two Pointers Technique":

import java.io.; import java.util.;

public class Solution {

public static void main(String[] args) {

    Scanner sc=new Scanner(System.in);
    String A=sc.next();
    int left = 0, right = A.length()-1;

    while(left < right) {
        if(A.charAt(left) != A.charAt(right)) {
            System.out.println("No");
            return;
        }
        left++;
        right--;
    }

    System.out.println("Yes");
}

}

Not able to submit the code even though all test cases are getting passed. It's showing error "Submission cannot be processed".

import java.io.; import java.util.;

public class Solution {

public static void main(String[] args) {

    Scanner sc=new Scanner(System.in);
    String A=sc.next();
    /* Enter your code here. Print output to STDOUT. */
    int start=0;
    int end=A.length()-1;
    boolean isPalindrome=true;
     while(start<=end){
        if(A.charAt(start)!=A.charAt(end)){
            isPalindrome=false;
            break;
        }else{
            start++;
            end--;
        }
    }
    System.out.println(isPalindrome?"Yes":"No");
    sc.close();

}

}

boolean isPalindrome = true;

    for (int i = 0; i < A.length() / 2; i++) {
        if (A.charAt(i) != A.charAt(A.length() - 1 - i)) {
            isPalindrome = false;
            break;
        }
    }

    if (isPalindrome) {
        System.out.println("Yes");
    } else {
        System.out.println("No");
    }   

import java.io.; import java.util.;

public class Solution {

public static void main(String[] args) {

    Scanner sc=new Scanner(System.in);
    String A=sc.next();
    StringBuffer s = new StringBuffer(A);
    s.reverse();
    if(A.compareTo(s.toString())==0)
     System.out.println("Yes");
    else
     System.out.println("No");


}

}