// Java program for the above approach 
// contains only digits 
class string1 { 

	// Function to check if a string 
	// contains only digits 
	public static boolean
	onlyDigits(String str, int n) 
	{ 
		// Traverse the string from 
		// start to end 
		for (int i = 0; i < n; i++) { 

			// Check if character is 
			// not a digit between 0-9 
			// then return false
			if (str.charAt(i) < '0'
				|| str.charAt(i) > '9') { 
				return false; 
			} 
		} 
		// If we reach here, that means 
		// all characters were digits.
		return true; 
	} 

	// Driver Code 
	public static void main(String args[]) 
	{ 
		// Given string str 
		String str = "1a234"; 
		int len = str.length(); 

		// Function Call 
		System.out.println(onlyDigits(str, len)); 
	} 
}