Java.java

[package]>java.util.*
        Random
        >Methods:
        nextInt();
        nextFloat(); // etc ...
        GregorianCalendar
        >Methods:
        calendar.get(constant);
        calendar.setTimeInMillis(long);
        calendar.setTime(Date);
        >Constants:
        GregorianCalendar.DAY_OF_MONTH
        GregorianCalendar.YEAR
        GregorianCalendar.MONTH(0-->11)
        Date
        >Methods:
        setTime(long);
        getTime():long

        [package]>java.math.*
        BigInteger
        BigDecimal

        UNCLASSIFIED
        >Instructions:
        // copy arrays
        System.arraycopy(src,srcStartIndex,dst,dstStartIndex,length);

        // character and char
        Character.isUpperCase(char);
        char c=Character.toLowerCase(char);

        // convert array to string (can be used inside toString() )
        Arrays.toString(array); // like this [a, b, d, o]

        >Methods:
// parseInt
public static int parseInt(char[]charArray){
        int sum=0;
        for(char c:charArray){
        sum=(sum*10)+(c-'0');
        }
        return sum;
        }
// is Prime
public static boolean isPrime(int number){
        for(int divisor=2;divisor<=number/2;divisor++){
        if(number%divisor==0){
        return false;
        }
        }
        return true;
        }
// prime Factors
public static StackOfIntegers primeFactors(long number){
        StackOfIntegers stack=new StackOfIntegers(5);
        long temp=number;
        for(int i=2;i<=temp;i++){
        if(temp%i==0){
        stack.push(i); // prime factor
        temp/=i;
        i--;
        }
        }
        return stack;
        }