blocks|key|1494913|text|我相信它们最多可以有2%5E31-1个字符，因为它们由内部数组保存，并且在Java中数组是由整数索引的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1494914|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I believe they can be up to 2^31-1 characters, as they are held by an internal array, and arrays are indexed by integers in Java.

blocks|key|1280256|text|Integer.MAX_VALUE是字符串的最大大小%2B取决于你的内存大小，但是在sphere的在线判断上的问题是你不需要使用这些函数|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1280257|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Integer.MAX_VALUE is max size of string + depends of your memory size but the Problem on sphere's online judge you don't have to use those functions

blocks|key|1495076|text|您是否考虑过使用BigDecimal而不是String来保存您的数字？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1495077|entityMap^0|8|A|L|6|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

Have you considered using <code>BigDecimal</code> instead of <code>String</code> to hold your numbers?

blocks|key|1495142|text|堆的部分变得更糟了，我的朋友。UTF-16不保证限制为16位，可以扩展到32位|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1495143|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

The heap part gets worse, my friends. UTF-16 isn't guaranteed to be limited to 16 bits and can expand to 32

blocks|key|1495216|text|虽然理论上可以使用Integer.MAX_VALUE字符，但JVM可以使用的数组大小是有限制的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1495217|public+static+void+main(String...+args)+{
++++for+(int+i+=+0;+i+<+4;+i%2B%2B)+{
++++++++int+len+=+Integer.MAX_VALUE+-+i;
++++++++try+{
++++++++++++char[]+ch+=+new+char[len];
++++++++++++System.out.println("len:+"+%2B+len+%2B+"+OK");
++++++++}+catch+(Error+e)+{
++++++++++++System.out.println("len:+"+%2B+len+%2B+"+"+%2B+e);
++++++++}
++++}
}|code-block|syntax|javascript|1495218|在Oracle+Java+8上更新92打印|1495219|len:+2147483647+java.lang.OutOfMemoryError:+Requested+array+size+exceeds+VM+limit
len:+2147483646+java.lang.OutOfMemoryError:+Requested+array+size+exceeds+VM+limit
len:+2147483645+OK
len:+2147483644+OK|1495220|注意:在Java9中，字符串将使用byte[]，这意味着多字节字符将使用多个字节，并进一步减少最大值。如果你有所有四个字节的代码点，例如表情符号，你只能得到大约5亿个字符|1495221|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

While you can in theory Integer.MAX_VALUE characters, the JVM is limited in the size of the array it can use.

<pre><code>public static void main(String... args) {
 for (int i = 0; i &lt; 4; i++) {
 int len = Integer.MAX_VALUE - i;
 try {
 char[] ch = new char[len];
 System.out.println("len: " + len + " OK");
 } catch (Error e) {
 System.out.println("len: " + len + " " + e);
 }
 }
}
</code></pre>

on Oracle Java 8 update 92 prints

<pre><code>len: 2147483647 java.lang.OutOfMemoryError: Requested array size exceeds VM limit
len: 2147483646 java.lang.OutOfMemoryError: Requested array size exceeds VM limit
len: 2147483645 OK
len: 2147483644 OK
</code></pre>

Note: in Java 9, Strings will use byte[] which will mean that multi-byte characters will use more than one byte and reduce the maximum further. If you have all four byte code-points e.g. emojis, you will only get around 500 million characters

blocks|key|1280544|text|Java9使用byte[]来存储String.value，所以在Java9中只能获取大约1+1GB的字符串。另一方面，Java8可以有2+2GB的字符串。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1280545|我所说的字符是指“char”，有些字符在BMP中是不能表示的(比如一些表情符号)，所以它需要更多的字符(目前是2个)。|1280546|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

Java9 uses byte[] to store String.value, so you can only get about 1GB Strings in Java9. Java8 on the other hand can have 2GB Strings.

By character I mean "char"s, some character is not representable in BMP(like some of the emojis), so it will take more(currently 2) chars.

I'm trying <a href="http://www.spoj.com/problems/PALIN/" rel="noreferrer">The Next Palindrome</a> problem from Sphere Online Judge (SPOJ) where I need to find a palindrome for a integer of up to a million digits. I thought about using Java's functions for reversing Strings, but would they allow for a String to be this long?

How many characters can a Java String have?

Java

我正在尝试来自Sphere Online裁判(SPOJ)的问题，在那里我需要找到一个最多为一百万位数字的整数的回文。我想过使用Java的函数来反转字符串，但是它们允许字符串这么长吗？

问一个Java字符串可以有多少个字符？
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