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STATEMENT − Balance pans using given weights that are powers of a number.DESCRIPTION − In this problem we are given a pan based weighing machine. we are given a weight T and some other weights whose values are powers of a number a. We need to balance the pans using the given weights.Now, based on this we have this equation, T + (some power of a) = (some other power of a)Now, we should remember that there is exactly one weight corresponding to a power value.Example, T = 12 : a = 4Using the below values, we can balance the ... Read More
A balanced expression of parentheses is an expression that contains pairs of all sort of parentheses together in a correct order.this means that for every opening parentheses there is a closing parentheses in proper order of parentheses i.e. { }.let's take a few examples to understand the concept better −Expression − {([][]{})({}[]{})}Output − balancedExplanation − we can see that for every opening parentheses there is a closing parentheses. all the parentheses lying between an opening parentheses and closing parentheses in Pairs.Output − not balanceExplanation − there are some unordered pairs of parentheses which makes the the expression unbalanced.In this problem ... Read More
The @JsonSerialize annotation is used to declare custom serializer during the serialization of a field. We can implement a custom serializer by extending the StdSeralizer class. and need to override the serialize() method of StdSerializer class.Syntax@Target(value={ANNOTATION_TYPE, METHOD, FIELD, TYPE, PARAMETER}) @Retention(value=RUNTIME) public @interface JsonSerializeIn the below program, we can implement a custom serializer using @JsonSerialize annotationExampleimport java.io.*; import com.fasterxml.jackson.core.*; import com.fasterxml.jackson.databind.*; import com.fasterxml.jackson.databind.annotation.*; import com.fasterxml.jackson.databind.ser.std.*; public class JsonSerializeAnnotationTest { public static void main (String[] args) throws JsonProcessingException, IOException { Employee emp = new Employee(115, "Adithya", new String[] {"Java", "Python", "Scala"}); ObjectMapper mapper = new ... Read More
The JSON-lib API is a java library to serialize and de-serialize java beans, maps, arrays, and collections in the JSON format. We need to convert a JSON string to a bean by converting a string to JSON object first then convert this to a java bean.Syntaxpublic static Object toBean(JSONObject jsonObject, Class beanClass)In the below program, we can convert a JSON string to a bean.Exampleimport net.sf.json.JSONObject; import net.sf.json.JSONSerializer; public class ConvertJSONStringToBeanTest { public static void main(String[] args) { String jsonStr = "{\"firstName\": \"Adithya\", \"lastName\": \"Sai\", \"age\": 30, \"technology\": \"Java\"}"; JSONObject jsonObj = (JSONObject)JSONSerializer.toJSON(jsonStr); // convert String ... Read More
The @JsonIdentityInfo annotation is used when an object has a parent-child relationship in the Jackson library. The @JsonIdentityInfo annotation is used to indicate the object identity during the serialization and deserialization process. The ObjectIdGenerators.PropertyGenerator is an abstract place-holder class to denote a case where Object Identifier to use comes from a POJO property.Syntax@Target(value={ANNOTATION_TYPE, TYPE, FIELD, METHOD, PARAMETER}) @Retention(value=RUNTIME) public @interface JsonIdentityInfoExampleimport java.util.*; import java.io.*; import com.fasterxml.jackson.annotation.JsonIdentityInfo; import com.fasterxml.jackson.annotation.ObjectIdGenerators; import com.fasterxml.jackson.databind.ObjectMapper; public class JsonIdentityInfoTest { public static void main(String[] args) throws IOException { ObjectMapper mapper = new ObjectMapper(); User user = new User(115, "Raja", "Ramesh"); ... Read More
The JSONArray is a sequence of values, the external text is a string enclosed in square brackets with commas separating the values and internal text is an object having get() and opt() methods, we need to access those values by index. The element() method for adding or replacing those values. An array is an object that stores multiple values of the same type. It can hold both primitive types and object references. We can convert a JSON array to array by using the toArray() method of JSONArray class. This method produces an Object[] with the contents of JSONArray.Syntaxpublic Object[] toArray()Exampleimport java.util.Arrays; import net.sf.json.JSONArray; public ... Read More
The @Since annotation can use with the setVersion() method of the GsonBuilder class. This annotation can apply to a field in java class and accepts float as an argument. This argument represents the version number in which the field has serialized. The same can apply to the deserialization process.Syntax@Documented @Retention(value=RUNTIME) @Target(value={FIELD, TYPE}) public @interface SinceExampleimport com.google.gson.annotations.Since; import com.google.gson.Gson; import com.google.gson.GsonBuilder; public class GsonSinceAnnotationTest { public static void main(String[] args) { Employee emp = new Employee(); emp.setEmployeeName("Raja Ramesh"); emp.setEmployeeId(125); emp.setEmployeeTechnology("Java"); emp.setEmploeeAddress("Hyderabad"); System.out.println("Since version ... Read More
To combine, use GROUP_CONCAT() function to combine some attributes in two rows into one. As a separator, use hyphens.Let us first create a table −mysql> create table DemoTable1386 -> ( -> Title varchar(255), -> Name varchar(60) -> ); Query OK, 0 rows affected (0.67 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1386 values('Introduction to MySQL', 'Paul DuBois'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1386 values('Java in Depth', 'Khalid Mughal'); Query OK, 1 row affected (0.48 sec) mysql> insert into DemoTable1386 values('Introduction to MySQL', 'Russell Dyer'); Query OK, ... Read More
To find the closest pair from two sorted array, the Java code is as follows −Example Live Demopublic class Demo { void closest_pair(int my_arr_1[], int my_arr_2[], int arr_1_len, int arr_2_len, int sum){ int diff = Integer.MAX_VALUE; int result_l = 0, result_r = 0; int l = 0, r = arr_2_len-1; while (l=0){ if (Math.abs(my_arr_1[l] + my_arr_2[r] - sum) < diff){ result_l = l; result_r = r; ... Read More
The @Until annotation can use with the setVersion() method of the GsonBuilder class. This annotation can apply to a field in java class and accepts float as an argument. This argument represents the version number in which the field has serialized. The @Until annotation can manage the versioning of JSON classes in web-services.Syntax@Documented @Retention(value=RUNTIME) @Target(value={FIELD, TYPE}) public @interface UntilExampleimport com.google.gson.annotations.Until; import com.google.gson.Gson; import com.google.gson.GsonBuilder; public class GsonUntilAnnotationTest { public static void main(String[] args) { Employee emp = new Employee(); emp.setEmployeeName("Adithya"); emp.setEmployeeId(115); emp.setEmployeeTechnology("Python"); emp.setEmploeeAddress("Pune"); ... Read More