This deals with SQL. Left outer join preserves the unmatched rows from the first (left) table, joining them with a NULL row in the shape of the second (right) table.

In the context of Core Java, it’s important to note that Java itself is a programming language and does not directly deal with SQL or database operations. However, if you are referring to database concepts, particularly SQL, a left outer join is a relational database operation that returns all the rows from the left table and the matching rows from the right table. If there is no match, NULL values are returned for columns from the right table.

Here’s a brief explanation using SQL syntax:

sql

SELECT *

FROM left_table

LEFT OUTER JOIN right_table ON left_table.column_name = right_table.column_name;

In this query, all rows from the left_table will be included in the result set, and the matching rows from the right_table will be included as well. If there is no match, columns from the right_table will contain NULL values.

It’s important to mention that the concept of left outer join is related to databases and SQL, not specifically to Core Java. In Java, you might use JDBC or an ORM (Object-Relational Mapping) framework to interact with a database and perform such operations.