Code Review

String glue(String str1, String str2) {
    if (str1 == null || str2 == null) {
        return "";
    }
    return str1.concat(str2);
}

int finedIndexX(String str) {
    if (str == null || str.isEmpty()) {
        return -1;
    }
    return str.indexOf('x');
}

boolean finedFistWordInString(String str, String start) {
    if (str == null || str.isEmpty()) {
        return false;
    }
    return str.startsWith(start);
}

@Test
void glueTest1() {
    StringUtil stringUtil = new StringUtil();

    String result = stringUtil.glue("basil", "Aka");

    Assertions.assertEquals("basilAka", result);
}

@Test
void glueTest2() {
    StringUtil stringUtil = new StringUtil();

    String result = stringUtil.glue("", "");

    Assertions.assertEquals("", result);
}

@Test
void stringGlueTest2() {
    StringUtil stringUtil = new StringUtil();
    String actual = stringUtil.stringGlue("","");
    Assertions.assertEquals("", actual);
}

@Test
void stringGlueTest3() {
    StringUtil stringUtil = new StringUtil();
    String actual = stringUtil.stringGlue(null,null);
    Assertions.assertEquals("", actual);
}

public String glueText(String str1, String str2) {
    String result = null;

    if (str2 != null) {
        assert str1 != null;
        result = str1.concat(str2);
    }

    return result;
}

public boolean equalsStrings(String str1, String str2) {
    boolean result = false;

    if (str1 != null && str2 != null) {
        result = str1.equals(str2);
    }
    if (str1 == null && str2 == null) {
        result = true;
    }

    return result;
}

public boolean sameArrays(String[] str1, String[] str2) {
    boolean result = false;

    Arrays.sort(str1);
    Arrays.sort(str2);

    if (Arrays.equals(str1, str2)) {
        result = true;
    }

    return result;
}