Amazon Software Development Engineer interview questions

Coding exercise: Find occurrence of character in a string using Java collection hashMap. e.i: Given a string " Amazon Web Services" the output should be: Character a appears 2 times Character b appears 1 times Character c appears 1 times Character d appears 0 times Character e appears 3 times Character f appears 0 times Character g appears 0 times Character h appears 0 times Character i appears 1 times Character j appears 0 times Character k appears 0 times Character l appears 0 times Character m appears 1 times Character n appears 1 times Character o appears 1 times Character p appears 0 times Character q appears 0 times Character r appears 1 times Character s appears 2 times Character t appears 0 times Character u appears 0 times Character v appears 1 times Character w appears 1 times Character x appears 0 times Character y appears 0 times Character z appears 1 times