Own Class Scanner, problem with output and input ^D

Question

I need to write my Scanner. The problem is that if I enter data from the console into IDEA as follows:

Input: "1 2^D" Output: "" What should output: "1 2"

Input: "1 2 3 4 5 6 7" Output: "1 2 3 4 5 6" What should output: "1 2 3 4 5 6 7"

What could be the problem? And if you suddenly know how you can fix it? Code:

import java.io.*;
import java.util.Arrays;

public class OwnScanner {
    private final Reader reader;
    private final char[] Buffer = new char[1024];
    private int currIndexInBuffer = 0;
    private int size = 0;
    private char symbol;
    private final char charNegOne = ((char) -1);
    private final StringBuilder outputBuilder = new StringBuilder();

    public OwnScanner(String toRead) {
        this.reader = new StringReader(toRead);
    }

    public OwnScanner(InputStream toRead) {
        this.reader = new InputStreamReader(toRead);
    }

    public OwnScanner(FileInputStream toRead) {
        this.reader = new InputStreamReader(toRead);
    }

    private char nextChar() throws IOException {
        if (currIndexInBuffer >= size) {
            currIndexInBuffer = 0;
            size = reader.read(Buffer, 0, 1024);
        }
        if (size == -1) {
            return charNegOne;
        } else {
            return Buffer[currIndexInBuffer++];
        }
    }

    private boolean skipWhitespaceAndLetter() throws IOException {
        while ((symbol = nextChar()) != charNegOne) {
            if (Character.isDigit(symbol)) {
                currIndexInBuffer--;
                return true;
            }
        }
        return false;
    }

    private boolean skipWhitespaceAndDigit() throws IOException {
        while ((symbol = nextChar()) != charNegOne) {
            if (!(Character.isDigit(symbol)) & !(Character.isWhitespace(symbol))) {
                currIndexInBuffer--;
                return true;
            }
        }
        return false;
    }

    public boolean hasNext() throws IOException {
        return skipWhitespaceAndDigit();
    }

    public boolean hasNextInt() throws IOException {
        return skipWhitespaceAndLetter();
    }

    public char nextSym() throws IOException {
        return nextChar();
    }

    public void close() throws IOException {
        reader.close();
    }

    public boolean hasNextLine() throws IOException {
        int startIndex = currIndexInBuffer;
        while ((symbol = nextChar()) != charNegOne) {
            if (System.lineSeparator().contains(String.valueOf(symbol))) {
                currIndexInBuffer = startIndex;
                return true;
            }
        }
        return false;
    }

    public String next() throws IOException {
        outputBuilder.setLength(0);
        skipWhitespaceAndDigit();
        while ((symbol = nextChar()) != charNegOne) {
            if (Character.isDigit(symbol) | Character.isWhitespace(symbol)) {
                break;
            }
            outputBuilder.append(symbol);
        }
        return String.valueOf(outputBuilder);
    }

    public String nextLine() throws IOException {
        outputBuilder.setLength(0);
        while ((symbol = nextChar()) != charNegOne) {
            if (System.lineSeparator().contains(String.valueOf(symbol))) {
                break;
            }
            outputBuilder.append(symbol);
        }
        return String.valueOf(outputBuilder);
    }

    public int nextInt() throws IOException {
        outputBuilder.setLength(0);
        skipWhitespaceAndLetter();
        while ((symbol = nextChar()) != ((char) -1)) {
            if (Character.isLetter(symbol) | Character.isWhitespace(symbol)) {
                break;
            }
            outputBuilder.append(symbol);
        }
        return Integer.parseInt(String.valueOf(outputBuilder));
    }

    public static void main(String[] args) throws IOException {
         OwnScanner sc = new OwnScanner(System.in);
         while (sc.hasNextLine()) {
             System.out.println(sc.nextInt());
         }
    }
}

It seems to me that the error may be in skipWhitespaceandLettre or skipWhitespaceandDigit, but I'm not sure.