Design Pattern to implement Business Rules with hundreds of if else in java

You should check out the Rules Design Pattern http://www.michael-whelan.net/rules-design-pattern/. It looks very similar to the example code you gave and consists of a base interface that defines a method for determining if a rule is satisfied and then various concrete implementations per different rules. As I understand it, your switch statement would turn into some sort of simple loop that just evaluates things until your composition of rules is either satisfied or fails.

interface IRule {
    bool isSatisfied(SomeThing thing);
}

class RuleA: IRule {
    public bool isSatisfied(SomeThing thing) {
        ...
    }
}

class RuleB: IRule {
    ...
}

class RuleC: IRule {
    ...
}

Composition Rules:

class OrRule: IRule {
    private readonly IRule[] rules;

    public OrRule(params IRule[] rules) {
        this.rules = rules;
    }

    public isSatisfied(thing: Thing) {
        return this.rules.Any(r => r.isSatisfied(thing));
    }
}

class AndRule: IRule {
    private readonly IRule[] rules;

    public AndRule(params IRule[] rules) {
        this.rules = rules;
    }

    public isSatisfied(thing: Thing) {
        return this.rules.All(r => r.isSatisfied(thing));
    }
}

// Helpers for AndRule / OrRule

static IRule and(params IRule[] rules) {
    return new AndRule(rules);
}

static IRule or(params IRule[] rules) {
    return new OrRule(rules);
}

Some service method that runs a rule on a thing:

class SomeService {
        public evaluate(IRule rule, Thing thing) {
            return rule.isSatisfied(thing);
        }
    }

Usage:

// Compose a tree of rules
var rule = 
    and (
        new Rule1(),
        or (
            new Rule2(),
            new Rule3()
        )
    );

var thing = new Thing();

new SomeService().evaluate(rule, thing);

This was also answered here: https://softwareengineering.stackexchange.com/questions/323018/business-rules-design-pattern