The BigDecimal class contains an internal cache of frequently used numbers e.g. 0 to 10. The BigDecimal.valueOf() methods are provided in preference to constructors with similar type parameters i.e. in the below example a is preferred to b.
BigDecimal a = BigDecimal.valueOf(10L); //Returns cached Object reference
BigDecimal b = new BigDecimal(10L); //Does not return cached Object reference
BigDecimal a = BigDecimal.valueOf(20L); //Does not return cached Object reference
BigDecimal b = new BigDecimal(20L); //Does not return cached Object reference
BigDecimal a = BigDecimal.valueOf(15.15); //Preferred way to convert a double (or float) into a BigDecimal, as the value returned is equal to that resulting from constructing a BigDecimal from the result of using Double.toString(double)
BigDecimal b = new BigDecimal(15.15); //Return unpredictable result