Java – Kotlin string maximum length? (Kotlin files with long strings do not compile)

According to this answer Java can hold up to 2^31 – 1 character. I tried to do benchmarking and stuff, so I tried to create a lot of strings and write them to a file like this :

import java.io.*

fun main() {
    val out = File("ouput.txt").apply { createNewFile() }.printWriter()
    sequence {
        var x = 0
        while (true) {
            yield("${++x} ${++x} ${++x} ${++x} ${++x}")
        }
    }.take(5000).forEach { out.println(it) }
    out.close()
}

The output.txt file contains the following:

1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
16 17 18 19 20
21 22 23 24 25
// ... 5000 lines

Then I copied all the contents of the file into a string in order to benchmark some functions, so it looks like this:

import kotlin.system.*

fun main() {
    val inputs = """
        1 2 3 4 5
        6 7 8 9 10
        11 12 13 14 15
        16 17 18 19 20
        21 22 23 24 25
        // ... 5000 lines
        24986 24987 24988 24989 24990
        24991 24992 24993 24994 24995
        24996 24997 24998 24999 25000

""".trimIndent()
    measureNanoTime {
        inputs.reader().forEachLine { line ->
            val (a, b, c, d, e) = line.split(" ").map(String::toInt)
        }
    }.div(5000).let(::println)
}

The total character count of the file/string is 138894

String can hold up to 2147483647

But the Kotlin code did not compile (last file) it throws a compilation error:

e: org.jetbrains.kotlin.codegen.CompilationException: Back-end (JVM) Internal error: wrong bytecode generated
 more lines
The root cause java.lang.IllegalArgumentException was thrown at: org.jetbrains.org.objectweb.asm.ByteVector.putUTF8(ByteVector.java:246)
    at org.jetbrains.kotlin.codegen.TransformationMethodVisitor.visitEnd(TransformationMethodVisitor.kt:92)
    at org.jetbrains.kotlin.codegen.FunctionCodegen.endVisit(FunctionCodegen.java:971)
    ... 43 more
Caused by: java.lang.IllegalArgumentException: UTF8 string too large

Here is the total log of stack trace exceptions: https://gist.github.com/Animeshz/1a18a7e99b0c0b913027b7fb36940c07

There is a restriction in Java class files that string constants must be 16 bits in length, ie. 65535 bytes (not characters) is the maximum length of a string in the source code.

The class File Format