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8中基本数据类型及对应的封装类型:
- boolean/1 --public final class Boolean implements java.io.Serializable,Comparable<Boolean>
- byte/8 --public final class Byte extends Number implements Comparable<Byte>
- char/16 --public final class Character implements java.io.Serializable, Comparable<Character>
- short/16 --public final class Short extends Number implements Comparable<Short>
- int/32 --public final class Integer extends Number implements Comparable<Integer>
- float/32 --public final class Float extends Number implements Comparable<Float>
- long/64 --public final class Long extends Number implements Comparable<Long>
- double/64 --public final class Double extends Number implements Comparable<Double>
缓存池:
1、类型
private static class
2、常见缓存池
ByteCache
static final Byte cache[] = new Byte[-(-128) + 127 + 1];
ShortCache
static final Short cache[] = new Short[-(-128) + 127 + 1];
IntegerCache
static final int low = -128;
上限不固定,常见的是127,可通过更改jvm 参数-Djava.lang.Integer.IntegerCache.high=##,修改上限,最大不能大于Integer.MAX_VALUE - (-low) -1
LongCache
static final Long cache[] = new Long[-(-128) + 127 + 1];
CharacterCache
static final Character cache[] = new Character[127 + 1];
Boolean
public static final Boolean TRUE = new Boolean(true);
public static final Boolean FALSE = new Boolean(false);