A simple question: What is the maximum size (in bytes or characters) of a String object in Java?
Some background info: I want to build a SQL statement (INSERT INTO tbl VALUES (...), (...), ...) and I don't want to exceed the size of the object.
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4 Answers
Strings contain an array of chars, so I think you can have at most 2^31 - 1 characters in a Java String. This is the value of Integer.MAX_VALUE.
Any String larger than that, and you can't even index all of the elements.
from the source code
class String implements java.io.Serializable {
private char value[]; // 4 bytes + 12 bytes of array header
private int offset; // 4 bytes
private int count; // 4 bytes
}
what ever the value of Integer.MAX_VALUE is (which on most systems will be 2^31 -1)
this requires 4GB of memory though so its a very large amount (java uses 16 bit unicode)
so the minimum of Integer.MAX_VALUE and the available memory
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It sounds like you want to insert many rows. Use a PreparedStatement and batch parameters. https://stackoverflow.com/a/3786127/1172714.
Please note that assembling a SQL statement as a String is a dangerous practice. Instead use a prepared statement http://docs.oracle.com/javase/tutorial/jdbc/basics/prepared.html
1 Comment
Barranka
Thank you. I know it can be dangerous, but this specific program is for my personal use, and I can take the luxury of being "not so formal" ;-)
Theoretically it could be Integer.MAX_VALUE chars long.
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