kundana sharma

interface Creature{void jump();} class bird implements creature{ long height = 156; public void jump(){ System.out.println("HOP HOP"); } } public class sparrow extends bird{ public void jump(){ System.out.println("Hop and chirp,hop and chirp"); } public static void main(String [] args){ Sparrow s1 = new Sparrow(); Sparrow s2 = new Sparrow(); Sparrow s3 = new Sparrow(); s3=s1; s1=s2; s2=null; s3=s1; } }
At line 20 how many objects are available for Garbage collection?
My Ans is 2 objects will be Garbage Collected.But some say it to be 4.
My Solution:
s1--->SO1. At line 13.Lets acronym Sparrow Object as SO;
s2--->SO2. At line 14.
s3--->SO3. At line 15.
After line 16:s1--->SO3 ,s2--->SO2,s3--->SO3.So SO1 available for GC.
After line 17:s1--->SO3 ,s2--->SO3,s3--->SO3.So SO2 available for GC.
After line 18:s1--->SO3 ,s2--->null,s3--->SO3.
After line 19:As both s1 and s3 refer to same object, nothing much wrt GC is going to happen in this line.
Is this correct? some say 4 objects will be Garbage collected.

I am solving this problem:A user inputs a string consisting only alphabets and numbers (qqw123sfw33434).Now my job is to print an alphabet and a number like (q1q2w3s3f3w434) .I am able to extract both the both the Strings and integers into separate arrays.Now I need a logic to print one element of the array followed by another:
My code:
public void formatInput(){ String [] tokensStrings = str.split("\\d"); // splitting string to get all alphabets array String [] tokensInts = str.split("[a-zA-Z]"); //splitting string to get all alphabets array int len1=tokensStrings.length; int len2=tokensInts.length; int smallest = (len1>len2)?len2:len1; System.out.println(smallest); //PLease give me a logic to print tokensStrings[i] +" "+tokensInts[i] } }
I know I am getting null pointer exception

Thank you .
I understood this after I posted the question.

This question is confusing me a lot.
Can some one clarify this.please explain both the cases:enabling assertions and disabling assertions.
public class AssertDemo{ public static void main(String [] args){ boolean assertEnabled=false; assert assertEnabled=true; System.out.println("Assertions are "+(assertEnabled ? "Enabled" : "Disabled" )); } }

Thanks Martin. e.printStackTrace() helped.I didn't iterate through ResultSet.I fixed it.
Will get back If some problem arises.

There is a table called Student whose structure is like this
ID (PK) (Number) | Name (varchar2) | Class (number) |
I am connecting to a remote Oracle db.\
String url="jdbc:oracle:thin:@sthariqu-in:1521:ORCL"; String user="hr"; String password="hr"; int studentId; int isbn; try{ Class.forName("oracle.jdbc.driver.OracleDriver"); Connection conn= DriverManager.getConnection(url, user, password); System.out.println("Enter studentId:"); studentId=Console.readInt(); // System.out.println("Enter ISBN:"); // isbn=Console.readInt(); PreparedStatement pStatement; ResultSet rs1; pStatement = conn.prepareStatement("select class from student where id=?"); pStatement.setInt(1,studentId); rs1=pStatement.executeQuery(); int cls=rs1.getInt("CLASS"); System.out.println("printing "+cls); conn.close(); }catch(ClassNotFoundException e){ System.out.println("class not found'"); } catch (SQLException e) { System.out.println("SQLException occured"); } }
My Question: an SQL exception when it comes to line no 19.(when I debug the cursor jumps to line no 26 from 19 )I am not able to figure out what is happening.
I know that there is problem with result set,but I am not able to fix it.
thank you in advance.

what does ^ do in java? I know that it is XOR which means it returns true only if both the arguments are true.
but I am not able to understand this.
public int xoring(int x,int y){
return (x^y);
what does this method do?please explain with an example.
The whole code snippet is this:
public class xoring{ public static void main(String [] args){ int xo; abc a = new abc(); xo=a.xoring(111,5); System.out.println(xo); } } class abc{ public int xoring(int x,int y){ return (x^y); } }

can you please explain what is happening from declaration of the 2d array through till end.

I am stuck here.
String day="select extract(day from from_date) from month_txn where account_no="+accno; Statement st2; ResultSet rs2; st2=conn.createStatement(); rs2=st2.executeQuery(day);
I am not able to make out What result set contains.Is it an array of ints?
please help Dey
My task:I want to calculate interest for an account_no at the end of the month.
Sample database:From_date Account_no balance 13-Dec-12 8:34:54 PM 190 44534.90 14-Dec-12 8:34:54 PM 191 44534.90 15-Dec-12 8:34:54 PM 193 44534.90 15-Dec-12 8:34:54 PM 194 44534.90 16-Dec-12 8:34:54 PM 191 44534.90 19-Dec-12 8:34:54 PM 191 44534.90 17-Dec-12 8:34:54 PM 196 44534.90 18-Dec-12 8:34:54 PM 192 44534.90
Code for calculating interest: try { sqlAccNo="select balance from month_txn where account_no="+accno; day="select extract(day from from_date) from month_txn where account_no="+accno; Statement st2; ResultSet rs2; st2=conn.createStatement(); rs2=st2.executeQuery(day); st=conn.createStatement(); rs=st.executeQuery(sqlAccNo); while(rs2.next()){ int rowCount1=rs2.getRow(); System.out.println(rowCount1); } while (rs.next()) { double principle=rs.getDouble(1); System.out.println(principle); interest =interest+(principle*0.02688*0.08); //Interest cal: (balance on day[0])*(day[1]-day[0])*roi(8%pa) //.I need a day array for the shown calculation. System.out.println("Interest is "+interest); int rowCount = rs.getRow(); System.out.println(rowCount); }

I am not able to make out how to extract timestamp into result set and then use it.
please help.

I have a column name from_date as a timestamp in my Oracle Database.
Sample data: from_Date Account_NO balance 13-Dec-12 8:34:54 PM 190 44534.90 27-Dec-12 7:41:54 PM 190 12574.80 21-Dec-12 6:561:54 PM 190 4434.90 17-Dec-12 7:41:54 PM 190 4574.80
The Question is How can I extract only the day part from the database using JDBC in java code.I mean I just need the '13' part in 13-Dec-12 7:41:54 PM ,'27' part in 27-Dec-12 7:41:54 PM.
I want the data to be in an array in increasing order.
please help I am not well versed in java.