I had one table that has no primary key .But Hibernate takes all columns as composite primary keys and generated 2 POJOs .
when Iam retrieving the records from that table the query is executed correctly ,ie Iam getting exact list size but result set is showing null.

Your code would help us....

What part of the result is null?

I had Scheme table that has no primary key .It had 3 fields
schemeCode,schemeName,schemeRate.The hibernate-reveng.xml file
created 2 POJOS.ie Scheme.java,SchemeId.java.
The code for Scheme.java like this-----
private SchemeId id;

public Scheme() {
}

public Scheme(SchemeId id) {
this.id = id;
}
//getter& setter for id property

The code for SchemeId.java like this-----

private String schemeCode;
private String schemeName;
private BigDecimal schemeRate;
//getter& setters for above 3 properties

I am trying to execute query ie like this
sql="from Scheme obj where obj.id.schemeCode='A002'"
qry=session.createQuery(sql);
Output of qry.list() showing null
But

qry.list.size()------It showing correct list size

If i understand correctly..You get the list size but all the values in the objects are null..I hope you would have made an mistake in the mapping files...Can you post that too for us?

Did u generate the mapping file or you did it on your own?