java.math.BigDecimal cannot be cast to java.lang.Integer

This error occurs when you try to cast a BigDecimal object to an Integer object. BigDecimal is a class in the Java math library used for handling arbitrary-precision decimal numbers while Integer is a class in the Java lang library used for handling integer numbers of fixed size.

To fix this error, you need to convert the BigDecimal object to an Integer object using the intValue() method. For example:

BigDecimal bigDecimal = new BigDecimal("10.5");
Integer integer = bigDecimal.intValue();

This will convert the BigDecimal object to an Integer object and store it in the integer variable.