Error while executing custom udf - hive

Question

Hi I have a hive table which has got data from sqoop so there is a string field fc which has got null values. all other values are in the form of numbers.
I have written a UDF so that I can get the value has 1000 is there is null in that column and if it is not null i should the same value.My udf code looks like below
package com.cascrmg.customudf;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
public class sample extends UDF {
int returnVal;
// Accept a string input
public int evaluate(Text input) {
// If the value is null, return a 1000
if (input == null) {
returnVal = 1000;
} else {
returnVal = Integer.parseInt(input.toString());
}
// Lowercase the input string and return it
return returnVal;
}
}
But when I add it and try to execute it, I get below errors.
Caused by: org.apache.hadoop.hive.ql.metadata.HiveException: Unable to execute method public int com.cascrmg.customudf.sample.evaluate(org.apache.hadoop.io.Text) on object com.cascrmg.customudf.sample#408e96d9 of class com.cascrmg.customudf.sample with arguments {null:org.apache.hadoop.io.Text} of size 1
at org.apache.hadoop.hive.ql.exec.FunctionRegistry.invoke(FunctionRegistry.java:993)
at org.apache.hadoop.hive.ql.udf.generic.GenericUDFBridge.evaluate(GenericUDFBridge.java:182)
at org.apache.hadoop.hive.ql.exec.ExprNodeGenericFuncEvaluator._evaluate(ExprNodeGenericFuncEvaluator.java:186)
at org.apache.hadoop.hive.ql.exec.ExprNodeEvaluator.evaluate(ExprNodeEvaluator.java:77)
at org.apache.hadoop.hive.ql.exec.ExprNodeEvaluator.evaluate(ExprNodeEvaluator.java:65)
at org.apache.hadoop.hive.ql.exec.SelectOperator.processOp(SelectOperator.java:77)
at org.apache.hadoop.hive.ql.exec.Operator.forward(Operator.java:815)
at org.apache.hadoop.hive.ql.exec.TableScanOperator.processOp(TableScanOperator.java:97)
at org.apache.hadoop.hive.ql.exec.MapOperator$MapOpCtx.forward(MapOperator.java:157)
at org.apache.hadoop.hive.ql.exec.MapOperator.process(MapOperator.java:497)
... 9 more
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.apache.hadoop.hive.ql.exec.FunctionRegistry.invoke(FunctionRegistry.java:969)
... 18 more
Caused by: java.lang.NumberFormatException: For input string: "null"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:580)
at java.lang.Integer.parseInt(Integer.java:615)
at com.cascrmg.customudf.sample.evaluate(sample.java:16)
Any help would be really appreciated.

Answer 1

Your input Text/String whichever you are passing as parameter to your function may contain "null" itself is the form of string or text only.
It means you are trying to compare "null"(which is a string ) with null so it will always gives you a false result.
so in this case if input is "null"(String) it will never be equal to null and if it false you are parsing that string to Int .Hence you are getting java.lang.NumberFormatException: For input string: "null" so you can check for both null and "null".
if (input == null||input=="null") {
returnVal = 1000;
} else {
returnVal = Integer.parseInt(input.toString());
}