Sequential storage of linear tables in Java implementation data structure

/** * @author Neosong * @date Sep, 2017 * 7:30:43 PM * Program of information: Define some linear structure operations * 1, define interfaces and define methods in them, interface is 100% Abstract class, there are only method headers, no method body */public interface Sqllist {int count ();//Seek length void clear ();//Empty Operation Boolean isempty ();  Null Boolean isfull ()//To determine if full void attend (t item);//attach operation void Insert (T item,int l);/insert operation void Delete (int i);//delete operation T  getelement (int i);//Fetch matrix int Locate (T item)//position}/* @date Sep, 2017 * 7:44:53 PM * Program of Information: Data Structure---Linear table--Realization of sequential table * 2. Implement the method defined in the interface/public class Sequencelist implements sqllist{//define the constructor to initialize the variable public Sequen Celist () {} public sequencelist (int size) {if (size>=0) {list= (t[]) New object[size];//initialize T type array list, cannot point to parent class object with subclass reference,
			Therefore, it is necessary to forcibly convert this.maxsize=size;
		Last=-1;
	else throw new RuntimeException ("initialization size cannot be less than 0" +size);
	
	
	
	
	private int last;//defines the position in which last element is saved the private int maxsize;//is used to define the maximum storage capacity of the order table, last<=maxsize private t[] list; Public T getlist (int index) {RetuRN List[index];
	public void setlist (int index,t value) {list[index]=value;
	public int GetLast () {return last;
	public void Setlast (int last) {this.last = last;
	public int getmaxsize () {return maxSize;
	The public void setmaxsize (int maxSize) {this.maxsize = maxSize;
	
	
	}//sequencelist[] List=new sequencelist[maxsize];
	Find length public int count () {return last+1;
		//Empty public void clear () {//setlast (-1);
	Setlast (-1);
	}//Determine if NULL public boolean IsEmpty () {return last==-1;  //Judge if full public boolean isfull () {return last==maxsize-1;//This place is wrong at the time you write it, no-1}//Additional---loops traverse to the last number, then add in public
	    	void attend (T item) {//To determine whether the linear table is full to enhance the robustness of the program if (Isfull ()) {System.out.println ("array is full");
	return;//End Method} List[++last]=item; //Insert List---Array, item---value l---position public void Insert (T item,int L) {//To determine if the array is full if (Isfull ()) {SYSTEM.OUT.P
			Rintln ("The array is full");
		Return //Determine if the value of L is correct if (l<1| | L>last+2) {System.out.println ("Incorrect location, please check");
		Return
		}//for (int i=last+1;i>l-1;i--) {//list[i]=list[i-1];//} List[l-1]=item; last++;//array last element position change}//delete list----array L----position public void Delete (int l) {///To determine whether the linear table is an empty if (IsEmpty ()) {Syst
			EM.OUT.PRINTLN ("Array is empty");
		Return } if (l<1| | L>count ()) {//This place calls the count () method, so when you return the last value in the Count method,//cannot use last++.
	        This will virtually increase the last value, so that when traversing the output array, the final number will be null System.out.println ("input data is incorrect");
		Return //formally delete code for (int i=l-1;i