About the length of a string literal constant in Java

Although this problem should be difficult to meet, but it will be confused. I do not know if you have encountered the case of writing SQL statements in Java code with strings, but if the length of the SQL statement string is too long, it will be an error. The code is as follows:

Code A

String str = "567890123456789...0123456789";//Because the string length is too long, omit the part, the length is 65535
System.out.println (Str.length ());   Compile an error: Error: (EUR) Java: constant string too long

Code b

String str = "67890123456789...0123456789";//Because the string length is too long, omit the part, the length is 65534
System.out.println (Str.length ());   Compile pass, run result: 65534

Code C

String str = "67890123456789...0123456789";//Because the string length is too long, omit part, length is 65534
str = "5" + str;
System.out.println (Str.length ());   Compile pass, run result: 65535

Inside a string is stored as a char array, and the length of the array is of type int, then the maximum allowable length for string is Integer.max_value = 2^31-1 = 2147483647. And because the characters in Java are stored in 16-bit, it probably takes 4GB of memory to store the maximum length of the string.
But this is only for string variables, if it is string constants, such as "ABC", "1234" and so on in the code of string str, then the maximum allowable length depends on the size of the string in the constant pool, which is the storage format of the string in the class format file:

Constant_utf8_info {
    u1 tag;
    U2 length;
    U1 bytes[length];
}

U2 are unsigned 16-bit integers, so the maximum length of string str theoretically allowed is 2^16-1=65535. However, the actual test indicates that the maximum allowable length is only 65534, exceeding the compile error.
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