对象属性和数组元素的初始默认值

package initialvalue.one;

public class Main {
    public char charVal;
    public byte byteVal;
    public short shortVal;
    public int intVal;
    public long longVal;
    public float floatVal;
    public double doubleVal;
    public boolean booleanVal;

    public Character charObj;
    public Byte byteObj;
    public Short shortObj;
    public Integer intObj;
    public Long longObj;
    public Float floatObj;
    public Double doubleObj;
    public Boolean booleanObj;

    @Override
    public String toString() {
        return "Main [charVal=" + charVal + ", byteVal=" + byteVal + ", shortVal=" + shortVal + ", intVal=" + intVal
                + ", longVal=" + longVal + ", floatVal=" + floatVal + ", doubleVal=" + doubleVal + ", booleanVal="
                + booleanVal + ", charObj=" + charObj + ", byteObj=" + byteObj + ", shortObj=" + shortObj + ", intObj="
                + intObj + ", longObj=" + longObj + ", floatObj=" + floatObj + ", doubleObj=" + doubleObj
                + ", booleanObj=" + booleanObj + "]";
    }

    public static void main(String[] args) {
        System.out.println("对象属性初始值...");
        System.out.println(new Main().toString());
        System.out.println("数组元素初始值...");
        char[] charArray=new char[3];
        byte[] byteArray=new byte[3];
        short[] shortArray=new short[3];
        int[] intArray=new int[3];
        long[] longArray=new long[3];
        float[] floatArray=new float[3];
        double[] doubleArray=new double[3];
        boolean[] booleanArray=new boolean[3];
        Integer[] intObjArray=new Integer[3];
        System.out.print("charArray:[");
        for(char tmp: charArray){
            System.out.print(tmp+",");
        }
        System.out.println("]");
        System.out.print("byteArray:[");
        for(byte tmp: byteArray){
            System.out.print(tmp+",");
        }
        System.out.println("]");
        System.out.print("shortArray:[");
        for(short tmp: shortArray){
            System.out.print(tmp+",");
        }
        System.out.println("]");
        System.out.print("intArray:[");
        for(int tmp: intArray){
            System.out.print(tmp+",");
        }
        System.out.println("]");
        System.out.print("longArray:[");
        for(long tmp: longArray){
            System.out.print(tmp+",");
        }
        System.out.println("]");
        System.out.print("floatArray:[");
        for(float tmp: floatArray){
            System.out.print(tmp+",");
        }
        System.out.println("]");
        System.out.print("doubleArray:[");
        for(double tmp: doubleArray){
            System.out.print(tmp+",");
        }
        System.out.println("]");
        System.out.print("booleanArray:[");
        for(boolean tmp: booleanArray){
            System.out.print(tmp+",");
        }
        System.out.println("]");
        System.out.print("intObjArray:[");
        for(Integer tmp: intObjArray){
            System.out.print(tmp+",");
        }
        System.out.println("]");
        /*
         * Output:
         * 对象属性初始值...
         * Main [charVal= , byteVal=0, shortVal=0, intVal=0, longVal=0, floatVal=0.0, doubleVal=0.0, booleanVal=false, charObj=null, byteObj=null, shortObj=null, intObj=null, longObj=null, floatObj=null, doubleObj=null, booleanObj=null]
         * 数组元素初始值...
         * charArray:[ , , ,]
         * byteArray:[0,0,0,]
         * shortArray:[0,0,0,]
         * intArray:[0,0,0,]
         * longArray:[0,0,0,]
         * floatArray:[0.0,0.0,0.0,]
         * doubleArray:[0.0,0.0,0.0,]
         * booleanArray:[false,false,false,]
         * intObjArray:[null,null,null,]
         */
    }

}

注：其实可以将数组的各元素看做数组对象的属性，如此对象属性和数组元素初始默认值就简化为对象属性默认值，基本类型的默认值为0（其中浮点型和双精度浮点型默认为0.0，字符型默认为空格，布尔型默认为false），引用类型的默认值为null。