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public native int hashCode();

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public V put(K key, V value) {

if (key == null)

return putForNullKey(value);

int hash = hash(key.hashCode());

int i = indexFor(hash, table.length);

for (Entry<K,V> e = table[i]; e != null; e = e.next) {

Object k;

if (e.hash == hash && ((k = e.key) == key || key.equals(k))) {

V oldValue = e.value;

e.value = value;

e.recordAccess(this);

return oldValue;

}

}

modCount++;

addEntry(hash, key, value, i);

return null;

}

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static inline intptr_t get_next_hash(Thread * Self, oop obj) {

intptr_t value = 0 ;

if (hashCode == 0) {

// This form uses an unguarded global Park-Miller RNG,

// so it‘s possible for two threads to race and generate the same RNG.

// On MP system we‘ll have lots of RW access to a global, so the

// mechanism induces lots of coherency traffic.

value = os::random() ;

} else

if (hashCode == 1) {

// This variation has the property of being stable (idempotent)

// between STW operations. This can be useful in some of the 1-0

// synchronization schemes.

intptr_t addrBits = intptr_t(obj) >> 3 ;

value = addrBits ^ (addrBits >> 5) ^ GVars.stwRandom ;

} else

if (hashCode == 2) {

value = 1 ; // for sensitivity testing

} else

if (hashCode == 3) {

value = ++GVars.hcSequence ;

} else

if (hashCode == 4) {

value = intptr_t(obj) ;

} else {

// Marsaglia‘s xor-shift scheme with thread-specific state

// This is probably the best overall implementation -- we‘ll

// likely make this the default in future releases.

unsigned t = Self->_hashStateX ;

t ^= (t << 11) ;

Self->_hashStateX = Self->_hashStateY ;

Self->_hashStateY = Self->_hashStateZ ;

Self->_hashStateZ = Self->_hashStateW ;

unsigned v = Self->_hashStateW ;

v = (v ^ (v >> 19)) ^ (t ^ (t >> 8)) ;

Self->_hashStateW = v ;

value = v ;

}

value &= markOopDesc::hash_mask;

if (value == 0) value = 0xBAD ;

assert (value != markOopDesc::no_hash, "invariant") ;

TEVENT (hashCode: GENERATE) ;

return value;

}

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package com.cxh.test1;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Set;

class People{

private String name;

private int age;

public People(String name,int age) {

this.name = name;

this.age = age;

}

public void setAge(int age){

this.age = age;

}

@Override

public boolean equals(Object obj) {

// TODO Auto-generated method stub

return this.name.equals(((People)obj).name) && this.age== ((People)obj).age;

}

}

public class Main {

public static void main(String[] args) {

People p1 = new People("Jack", 12);

System.out.println(p1.hashCode());

HashMap<People, Integer> hashMap = new HashMap<People, Integer>();

hashMap.put(p1, 1);

System.out.println(hashMap.get(new People("Jack", 12)));

}

}

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public V get(Object key) {

if (key == null)

return getForNullKey();

int hash = hash(key.hashCode());

for (Entry<K,V> e = table[indexFor(hash, table.length)];

e != null;

e = e.next) {

Object k;

if (e.hash == hash && ((k = e.key) == key || key.equals(k)))

return e.value;

}

return null;

}

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package com.cxh.test1;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Set;

class People{

private String name;

private int age;

public People(String name,int age) {

this.name = name;

this.age = age;

}

public void setAge(int age){

this.age = age;

}

@Override

public int hashCode() {

// TODO Auto-generated method stub

return name.hashCode()*37+age;

}

@Override

public boolean equals(Object obj) {

// TODO Auto-generated method stub

return this.name.equals(((People)obj).name) && this.age== ((People)obj).age;

}

}

public class Main {

public static void main(String[] args) {

People p1 = new People("Jack", 12);

System.out.println(p1.hashCode());

HashMap<People, Integer> hashMap = new HashMap<People, Integer>();

hashMap.put(p1, 1);

System.out.println(hashMap.get(new People("Jack", 12)));

}

}

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package com.cxh.test1;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Set;

class People{

private String name;

private int age;

public People(String name,int age) {

this.name = name;

this.age = age;

}

public void setAge(int age){

this.age = age;

}

@Override

public int hashCode() {

// TODO Auto-generated method stub

return name.hashCode()*37+age;

}

@Override

public boolean equals(Object obj) {

// TODO Auto-generated method stub

return this.name.equals(((People)obj).name) && this.age== ((People)obj).age;

}

}

public class Main {

public static void main(String[] args) {

People p1 = new People("Jack", 12);

System.out.println(p1.hashCode());

HashMap<People, Integer> hashMap = new HashMap<People, Integer>();

hashMap.put(p1, 1);

p1.setAge(13);

System.out.println(hashMap.get(p1));

}

}