The application gets a double value from the database. Database has and allows "null" values for a double type variable but in my java code I can't assign null values to the variable type double.
double var1 = null; -- this throws an error
Double var2 = null; -- no error thrown here
reason: double is a primitive datatype and thus can't initialize it to a null but we can assign a null to Double as it takes the input as an object which encapsulates a primitive datatype. its like a wrapper to the primitive datatype thus can be initiated to null
we can read the null value into our code as
double var1 = resultset.getDouble(columnIndex);
if the column has null it will return a zero
thus saving your variable from the null pointer exception!
double var1 = null; -- this throws an error
Double var2 = null; -- no error thrown here
reason: double is a primitive datatype and thus can't initialize it to a null but we can assign a null to Double as it takes the input as an object which encapsulates a primitive datatype. its like a wrapper to the primitive datatype thus can be initiated to null
we can read the null value into our code as
double var1 = resultset.getDouble(columnIndex);
if the column has null it will return a zero
thus saving your variable from the null pointer exception!
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