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Page 217 of 589
Check if a string contains only alphabets in Java using Regex
At first, convert the string into character array. Here, name is our string −char[] ch = name.toCharArray();Now, loop through and find whether the string contains only alphabets or not. Here, we are checking for not equal to a letter for every character in the string −for (char c : ch) { if(!Character.isLetter(c)) { return false; }Following is an example to check if a string contains only alphabets using RegexExamplepublic class Main { public static boolean checkAlphabet(String name) { char[] ch = name.toCharArray(); for (char c : ch) { ...
Read MoreCompare two Strings in Java
Compare two strings using compareTo() method in Java. The syntax is as follows −int compareTo(Object o)Here, o is the object to be compared.The return value is 0 if the argument is a string lexicographically equal to this string; a value less than 0 if the argument is a string lexicographically greater than this string; and a value greater than 0 if the argument is a string lexicographically less than this string.ExampleLet us now see an example −public class Demo { public static void main(String args[]) { String str1 = "Strings are immutable"; String ...
Read MoreIn how many ways we can convert a String to a character array using Java?
You can convert a String to a character array either by copying each element of the String to an array or, using the toCharArray() method.Copying each elementGet the String to be converted.Create an empty character array with the length of the String.The charAt() method of the String class returns the character at a particular position. Using this method copy each character of the String to the array.Exampleimport java.util.Arrays; import java.util.Scanner; public class StringToCharArray { public static void main(String args[]) { Scanner sc = new Scanner(System.in); System.out.println("Enter a String value: "); ...
Read MoreHow to execute an external program like windows media player in Java?
Using the Runtime classJava provides a class named java.lang.Runtime, using this class you can interface with the current environment.The getRunTime() (static) method of this class returns a Runtime object associated with the current application.The exec() method accepts a String value representing the command to execute a process in the current environment (system) and executes it.Therefore, to execute an external application using the Runtime class −Get the run time object using the getRuntime() method.Execute the required process by passing the path of it as a String value to the exec() method.Exampleimport java.io.IOException; public class Trail { public static void main(String ...
Read MoreHow do we initialize an array within object parameters in java?
You can initialize the array variable which is declared inside the class just like any other value, either using constructor or, using the setter method.ExampleIn the following Java example, we are declaring an instance variable of array type and initializing it from the constructor.public class Student { String name; int age; String subs[]; Student(String name, int age, String subs[]){ this.name = name; this.age = age; this.subs = subs; } public void display() { System.out.println("Name: "+this.name); System.out.println("Age :"+this.age); System.out.print("Subjects: "); for(int i = 0; i < subs.length; i++) { ...
Read MoreHow to copy a specific section of an array in Java?
Using copyOf() methodThe copyOf() method of the Arrays class (java.util package) accepts two parameters −an array (of any type).an integer value representing length.And copies the contents of the given array from starting position to given length and returns the new array.Exampleimport java.util.Arrays; public class CopyingSectionOfArray { public static void main(String[] args) { String str[] = new String[10]; //Populating the array str[0] = "Java"; str[1] = "WebGL"; str[2] = "OpenCV"; str[3] = "OpenNLP"; str[4] = "JOGL"; ...
Read MoreIs it possible to check if a String only contains ASCII in java?
Using regular expressionYou can find whether a particular String value contains ASCII characters using the following regular expression −\A\p{ASCII}*\zThe matches() method of the String class accepts a regular expression and verifies whether the current string matches the given expression if so, it returns true, else it returns false.Therefore, Invoke the matches() method on the input/required string by passing the above specified regular expression as a parameter.Exampleimport java.util.Scanner; public class OnlyASCII { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("Enter a string value: "); String input = ...
Read MoreHow to make elements of array immutable in Java?
No, you cannot make the elements of an array immutable.But the unmodifiableList() method of the java.util.Collections class accepts an object of the List interface (object of implementing its class) and returns an unmodifiable form of the given object. The user has only read-only access to the obtained list.And the asList() method of the ArrayList class accepts an array and returns a List object.Therefore, to convert an array immutable −Obtain the desired array.Convert it into a list object using the asList() method.Pass the obtained list as a parameter to the unmodifiableList() method.Exampleimport java.util.Arrays; import java.util.Collections; import java.util.List; public class UnmodifiableExample { ...
Read MoreHow to parse Date from String in the format: dd/MM/yyyy to dd/MM/yyyy in java?
The java.text package provides a class named SimpleDateFormat which is used to format and parse dates in required manner (local).One of the constructors of this class accepts a String value representing the desired date format and constructors SimpleDateFormat object.The format() method of this class accepts a java.util.Date object and returns a date/time string in the format represented by the current object.Therefore, to parse a date String to another date format −Get the input date string.Convert it into java.util.Date object.Instantiate the SimpleDateFormat class by passing the desired (new) format as string to its constructor.Invoke the format() method by passing the above ...
Read MoreWhat is ArrayStoreException in Java?
When you have created an array of a particular data type with fixed size and populate it if you store a value other than its datatype an ArrayStoreException is thrown at the run time.ExampleIn the following Java program, we are creating an Integer array and trying to store a double value in it.import java.util.Arrays; public class ArrayStoreExceptionExample { public static void main(String args[]) { Number integerArray[] = new Integer[3]; integerArray[0] = 12548; integerArray[1] = 36987; integerArray[2] = 555.50; integerArray[3] = 12548; ...
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