Java Articles

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The get() method of AbstractList class in Java

Daniol Thomas
Daniol Thomas
Updated on 30-Jul-2019 211 Views

The get() method of the AbstractList class is used to get the element at the specified position in the list. It returns the element at the position set as parameter.The syntax is as follows:public abstract E get(int index)Here, index is the index of the element to return.To work with the AbstractList class, import the following package:import java.util.AbstractList;The following is an example to implement get() method of the AbstractlList class in Java:Exampleimport java.util.LinkedList; import java.util.AbstractList; public class Demo {    public static void main(String[] args) {       AbstractList myList = new LinkedList();       myList.add(50);       ...

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How to set/insert null values to in to a column of a row using JDBC program?

Jennifer Nicholas
Jennifer Nicholas
Updated on 30-Jul-2019 7K+ Views

You can insert null values into a table in SQL in two ways:Directly inserting the value NULL into the desired column as:Insert into SampleTable values (NULL);Using ‘ ’ as nullInsert into SampleTable values (NULL);While inserting data into a table using prepared statement object you can set null values to a column using the setNull() method of the PreparedStatement interface.pstmt.setNull(parameterIndex, sqlType);ExampleAssume we have a table named cricketers_data in the database with the following contents:+------------+------------+---------------+----------------+-------------+ | First_Name | Last_Name  | Date_Of_Birth | Place_Of_Birth | Country | +------------+------------+---------------+----------------+-------------+ | Shikhar    | Dhawan     | 1981-12-05    | ...

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How to get the number of records in a table using JDBC?

Nitya Raut
Nitya Raut
Updated on 30-Jul-2019 548 Views

The ResultSet class doesn’t provide any direct method to get the number of records in a table.The beforeFirst() method navigates the pointer/curser of the ResultSet object to its default position before first.In the same way the last() method positions the cursor at the last row of the ResultSet object.Using these methods you can find the number of records in the current ResultSet object.ExampleAssume we have a table named customers table with contents as shown below:+----+---------+-----+---------+----------------+ | ID | NAME    | AGE | SALARY  | ADDRESS        | +----+---------+-----+---------+----------------+ | 1  | Amit    | 25  | 3000.00 ...

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How to get the datatype of a column of a table using JDBC?

Jennifer Nicholas
Jennifer Nicholas
Updated on 30-Jul-2019 3K+ Views

You can get the datatype of a column of a table using the getColumnType() method of the ResultSetMetaData class.//Retrieving the ResultSetMetaData object ResultSetMetaData rsmd = rs.getMetaData(); //getting the column type String column_name = rsmd.getColumnTypeName(2);Assume we have a table named employee_data in the database with the description as shown below:+----------+--------------+------+-----+---------+-------+ | Field    | Type         | Null | Key | Default | Extra | +----------+--------------+------+-----+---------+-------+ | id       | int(11)      | YES  |     | NULL    | | | Name     | varchar(255) ...

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How to get the size of a column of a table using JDBC?

Nitya Raut
Nitya Raut
Updated on 30-Jul-2019 2K+ Views

You can get the size of a column of a table using the getPrecision() method of the ResultSetMetaData class.//Retrieving the ResultSetMetaData object ResultSetMetaData rsmd = rs.getMetaData(); //getting the column type int size_name = rsmd. getPrecision(3);Assume we have a table named employee_data in the database with description as shown below:+----------+--------------+------+-----+---------+-------+ | Field    | Type         | Null | Key | Default | Extra | +----------+--------------+------+-----+---------+-------+ | id       | int(11)      | YES  |     | NULL    |       | | Name     | varchar(255) | YES  | ...

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How to delete a row from ResultSet object using JDBC?

Nitya Raut
Nitya Raut
Updated on 30-Jul-2019 1K+ Views

The deleteRow() method of the ResultSet interface deletes the current row from the current ResultSet object.//Deleting a column from the ResultSet object rs.deleteRow();Assume we have a table named Cricketers_Data with 6 records as shown below:+----+------------+------------+---------------+----------------+-------------+ | ID | First_Name | Last_Name  | Year_Of_Birth | Place_Of_Birth | Country     | +----+------------+------------+---------------+----------------+-------------+ | 1  | Shikhar    | Dhawan     | 1981-12-05    | Delhi          | India | | 2  | Jonathan   | Trott      | 1981-04-22    | CapeTown       | SouthAfrica | | 3 ...

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How to move the result set pointer to required position?

Vrundesha Joshi
Vrundesha Joshi
Updated on 30-Jul-2019 303 Views

The absolute() method of the ResultSet interface accepts an integer value representing the index of a row and moves the ResultSet pointer of the current ResultSet object to the specified position.Assume we have a table named cricketers_data with 6 records as shown below:+------------+------------+---------------+----------------+-------------+ | First_Name | Last_Name  | Date_Of_Birth | Place_Of_Birth | Country     | +------------+------------+---------------+----------------+-------------+ | Shikhar    | Dhawan     | 1981-12-05    | Delhi          | India       | | Jonathan   | Trott      | 1981-04-22    | CapeTown       | SouthAfrica | | Lumara   ...

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Create KeyValue Tuple from a List collection in Java

Krantik Chavan
Krantik Chavan
Updated on 30-Jul-2019 194 Views

To create KeyValue tuple from List collection, use the fromCollection() method. Let us first see what we need to work with JavaTuples. To work with KeyValue class in JavaTuples, you need to import the following package:import org.javatuples.KeyValue;Note: Download JavaTuples Jar library to run JavaTuples program. If you are using Eclipse IDE, then Right Click Project → Properties → Java Build Path → Add External Jars and upload the downloaded JavaTuples jar file. Refer the below guide for all the steps to run JavaTuples:Steps: How to run JavaTuples program in EclipseThe following is an example to create KeyValue Tuple from List ...

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How to fetch the value from a KeyValue Tuple in Java?

Nancy Den
Nancy Den
Updated on 30-Jul-2019 239 Views

To fetch the value from a KeyValue tuple in Java, use the getValue() method. Let us first see what we need to work with JavaTuples. To work with KeyValue class in JavaTuples, you need to import the following package:import org.javatuples.KeyValue;Note: Download JavaTuples Jar library to run JavaTuples program. If you are using Eclipse IDE, then Right Click Project → Properties → Java Build Path → Add External Jars and upload the downloaded JavaTuples jar file. Refer the below guide for all the steps to run JavaTuples:Steps: How to run JavaTuples program in EclipseThe following is an example to fetch the ...

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How to find the current row of a ResultSet object using JDBC?

Nitya Raut
Nitya Raut
Updated on 30-Jul-2019 782 Views

The getRow() method of the ResultSet class returns the row number at which the ResultSet pointer exists in the current instance.Assume we have a table named cricketers_data with 6 records as shown below:+------------+------------+---------------+----------------+-------------+ | First_Name | Last_Name  | Date_Of_Birth | Place_Of_Birth | Country     | +------------+------------+---------------+----------------+-------------+ | Shikhar    | Dhawan     | 1981-12-05    | Delhi          | India       | | Jonathan   | Trott      | 1981-04-22    | CapeTown       | SouthAfrica | | Lumara     | Sangakkara | 1977-10-27    | Matale     ...

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