eBay Software Engineer Intern interview questions

What's the difference between C++ and Java. I said something about pointers and he wanted me to go more in depth. What is the difference between string builder and string buffer. He sent me a code and make suggestions: import java.math.BigDecimal; public class CashCalculatorBasic { public BigDecimal getCalculatedAvailableBalance(BigDecimal currentBalance, BigDecimal totalDebits, BigDecimal totalCredits) { BigDecimal result = currentBalance.subtract(totalDebits).add(totalCredits); System.out.println("The calculated result is " + result); return result; } public static void main(String[] args) { new CashCalculatorBasic().getCalculatedAvailableBalance( new BigDecimal("1250.00"), new BigDecimal("250.00"), new BigDecimal("500.00")); } }